Effects of Essential Oils in the Treatment of Acute Rhinosinusitis: A Systematic Review

ABSTRACT

Objective

Basic science studies have shown that essential oils have antibacterial and anti‐inflammatory effects in the nasal mucosa. However, clinical studies examining the effect of essential oils on patient outcomes are limited. The aim of this systematic review is to evaluate the patient outcomes following treatment of acute rhinosinusitis with essential oils.

Methods

PubMed, Ovid, Cochrane, and Embase computerized searches were performed to include results published up to December 2023. Two independent reviewers (C.M.M. and W.J.) conducted data extraction following a predetermined protocol, with any discrepancies reviewed by the senior author (J.C.W.).

Results

Five RCTs investigated the treatment of rhinosinusitis with essential oils in capsule form. Essential oils included in the studies were Cineole, Myrtol (ELOM‐080), Sinupret (BNO 1016), and Tavipec. Significant improvements in rhinological symptoms were seen in Cinole compared to placebo, Cinole compared to an herbal compound similar in composition to Sinupret, Tavipec compared to placebo, and ELOM‐080 compared to placebo. Outcome measures included nasal obstruction, nasal drainage, facial pressure, headache, fatigue, and fever. Little difference in patient‐reported rhinological symptom improvement was seen in ELOM‐080 compared to BNO 1016 using a 5‐point Likert Scale. Minimal adverse effects were observed in patients treated with essential oils with the most common adverse effect being mild gastrointestinal upset.

Conclusion

Patients using essential oils reported improvement in acute rhinosinusitis symptoms in all studies reviewed, despite differences in methodology and outcome measures. These improvements were statistically significant in all the studies.

Level of Evidence

Level 1 based on “The Oxford 2011 Levels of Evidence”.

1. Introduction

Acute rhinosinusitis is characterized by inflammation of the sinuses with concomitant inflammation of the nasal passages lasting less than 12 weeks [1]. Clinical diagnosis requires patients to have two or more of the following symptoms: nasal blockage/obstruction/congestion, nasal discharge, facial pain/pressure, or reduction/loss of smell, with at least one of the symptoms being either nasal blockage/obstruction/congestion or nasal discharge [1]. Rhinosinusitis is common in the United States, affecting 12 to 15.2% of the adult population on an annual basis [2, 3]. The majority of patients with acute rhinosinusitis seek treatment within the first week given the severity of symptoms [4]. Despite bacterial infection being responsible in only 2% to 10% of cases [5, 6], there is problematic overutilization of antibiotic prescriptions.

A broad spectrum of essential oils have shown efficacy in several medical applications serving as anxiolytic agents [7], analgesic agents [8], and acne treatments [9]. In addition, essential oils have demonstrated antibacterial effects against a number of human pathogens, including common rhinosinusitis pathogens [10, 11, 12, 13, 14, 15]. In vitro studies have shown physiological benefits pertaining to rhinosinusitis, with evidence of essential oils contributing to increased chloride efflux and increased ciliary beat frequency in nasal mucosal cells [16]. These combined effects result in a greater mucociliary transport velocity [16], theoretically enhancing sinonasal mucous clearance.

While basic science studies have shown that essential oils have antibacterial, anti‐inflammatory, and increased mucociliary clearance activity, there are limited clinical studies examining essential oil effects on patient outcomes and quality of life. The aim of this systematic review is to evaluate patient outcomes following treatment of acute rhinosinusitis with essential oils.

2. Materials and Methods

A computerized search of PubMed, Ovid, Embase, and Cochrane databases was performed to identify all relevant manuscripts. Non‐human and non‐English studies were excluded. The review was registered through Prospero. Prospero registration number for this study is CRD42020157111. The population and intervention of interest were patients diagnosed with acute rhinosinusitis treated with essential oils. The main outcomes we were concerned with analyzing included patient‐reported outcomes, such as the severity of key symptoms (nasal congestion, rhinorrhea, headache, postnasal drip, and facial pain/pressure), as well as the duration until symptom resolution or significant improvement. Articles mapping to the medical subject heading: “acute rhinosinusitis, rhinosinusitis, and sinusitis” were combined into one group. Medical subject headings: “essential oil, essential oils, and Myrtol” were incorporated into a second group. The two groups were then cross‐referenced. Studies were excluded if they did not have full texts or could not be obtained. References of identified studies were reviewed for the adjunctive inclusion of relevant studies. Titles and abstracts were evaluated according to inclusion and exclusion criteria described hereafter. The evaluation was performed by two independent investigators (J.R.S. and C.L.F.) for all papers up to September 2021. This evaluation was repeated by another two independent investigators to include results published up to December 2023 (C.M.M and W.J.). All independent investigators were blinded to each other's results, with the search results additionally reviewed by the senior author (J.C.W.). The initial combined searches yielded 660 references, from which 416 duplicates were removed. Titles for 244 identified studies were reviewed, and 71 abstracts were assessed for eligibility. 9 full‐text articles were considered, with 3 articles [17, 18, 19] included in the final analysis [20]. The second round of combined searches yielded an additional 98 references, from which 14 duplicates were removed. Titles for 84 studies were reviewed, and 12 abstracts were assessed for eligibility. 3 full‐text articles were considered and 2 articles [21, 22] were added to the final analysis (Figure 1). The final analysis ultimately included a total of 5 articles, which encompassed a total of 1281 acute rhinosinusitis patients.

FIGURE 1.

PRISMA flow diagram for systematic review of essential oils and acute rhinosinusitis.

2.1. Risk of Bias

All studies exhibited a low risk of bias independently assessed by two reviewers via the Revised Cochrane risk of bias tool [23] for randomized trials, with the exception of Gottschlich et al. [17]. This study presented an overall high risk of bias arising from the non‐randomized and unblinded nature of the study (Table 1).

TABLE 1.

Risk of bias assessment of essential oils in acute rhinosinusitis.

Study	Kehrl [18] 2004	Tesche [19] 2008	Gottschlich [17] 2018	Dejaco [21] 2019	Pfaar [22] 2022
Domain 1: Risk of bias arising from randomization process	Low	Low	High	Low	Low
Justification	The study used a permuted block randomization method, ensuring a structured and balanced allocation of participants. There is no indication that allocation concealment was compromised.	The study used block randomization with a block length of 4, ensuring an even distribution of participants across treatment groups.	The study was a prospective, multicenter, parallel‐group, non‐interventional trial. The treatment allocation was not randomized; instead, patients received a recommendation for a specific treatment based on their physician's independent decision.	The study used randomized allocation and allocation concealment. No major baseline differences were observed between groups, indicating that the randomization process was properly conducted.	The study involved sequential random assignment of patients to the treatment or placebo groups with proper blinding and concealment, ensuring a low risk of bias.
Domain 2: Risk of bias due to deviations from the intended interventions	Low	Low	Some concerns	Low	Low
Justification	Blinding was maintained for participants, caregivers, and study personnel, reducing the likelihood of bias from deviations. Medication adherence was monitored through pill counts, further minimizing deviations from the intended intervention. The intention‐to‐treat analysis suggests an appropriate approach to analyzing participants based on their assigned intervention.	The study was double‐blind, and both the medication and placebo were indistinguishable. Compliance was monitored through returned medication counts. An intention‐to‐treat analysis was conducted, mitigating concerns regarding protocol deviations affecting outcomes.	Patients were not blinded to their treatment intervention, which could have influenced their perceptions and behaviors.	The study was double‐blind, and adherence was monitored by counting remaining capsules at each visit, minimizing deviations from the intended interventions. An intention‐to‐treat analysis was used to account for all randomized participants.	The study was double‐blinded, and the treatments were identical in appearance, taste, and smell, ensuring blinding was maintained.
Domain 3: Missing outcome data	Low	Low	Low	Low	Low
Justification	No major missing data concerns were reported, and the primary outcome was assessed at multiple time points, increasing data robustness.	The inclusion criteria required at least one follow‐up visit for analysis, but the study did not explicitly report dropout rates. However, given the structured follow‐up schedule (after 4 and 7 days), the risk of missing data bias is likely low. There is no indication that missing data influenced the results.	The study reports that only 5 of 228 patients were excluded due to protocol deviations. The missing data is minimal and evenly distributed between the groups, making it unlikely to influence results significantly.	Outcome data were available for nearly all participants, and no significant loss to follow‐up was reported. Data were collected with strict adherence to protocol, and no imputation was used for missing data. Any missing data were handled by clarifying unclear or illegible entries, ensuring that data were not missing due to reasons that could impact the outcomes.	The study employed statistical methods such as mixed model repeated measures (MMRM) for handling missing data, which assumed any missing data were missing at random.
Domain 4: Risk of bias in the measurement of the outcome	Low	Low	High	Low	Low
Justification	Outcomes were assessed using a standardized symptom‐sum score and confirmed by blinded external evaluation of sonographic imaging. Since the primary outcome measure was based on structured clinical examination and imaging, measurement bias is unlikely.	The outcome was assessed using both clinical and rhinoscopic examinations, in addition to the symptom‐sum score. The double‐blind design and the combination of assessment methods help minimize bias in measuring outcomes.	Both patients and physicians were aware of the treatment intervention, which may have influenced patient‐reported outcome measurements and physician assessments.	The outcome measures (MSS, SNOT‐22, and QoL) were predefined and relevant for the diagnosis of ARS. All outcome assessments were blinded, which minimizes the risk of bias in outcome measurement.	Outcome measurement methods were appropriate, and the investigators were blinded. Therefore, the risk of bias in outcome measurement remains low.
Domain 5: Risk of bias in the selection of the reported result	Low	Low	Some Concerns	Low	Low
Justification	The analysis followed a specified plan, and there was no indication that results were selectively reported based on multiple eligible outcome measurements or analyses.	The study specified its primary and secondary outcomes and used appropriate statistical methods, such as the Wei‐Lachin directional test, to analyze the data transparently, reducing the risk of selective reporting.	Assessors were not blinded to interventional groups, which could lead to bias in the way outcomes were measured or reported.	The statistical analysis and reporting followed a clear, defined plan. Despite the detailed primary and secondary outcome measures, no indication of selective outcome reporting was evident.	The study adhered to a specified analysis plan, and no selective reporting was observed. The analysis accounted for both primary and secondary endpoints in accordance with the predefined methodology.
Overall risk of bias	Low	Low	High	Low	Low

2.2. Inclusion and Exclusion Criteria

Studies included prospective clinical trials with utilization of essential oils to treat acute rhinosinusitis. Articles were excluded if they were: in vitro studies, reviews, cohort studies, case–control studies, or were not written in English.

2.3. Data Extraction

Extracted data included study design, country of origin, number of subjects, age range of subjects; male to female ratio of subjects, treatment intervention vs. control, sample size in treatment and control groups, duration of intervention (Table 2). Acute rhinosinusitis (ARS) as defined by study, outcomes measures, treatment outcomes, and adverse drug reactions were also extracted from each study (Table 3).

TABLE 2.

Study characteristics and demographics of included research participants.

Authors	Country of origin	Total number of subjects in the study	Age range (years)	Sample size in each treatment group	Ratio of female to male participants	Duration
Kehrl [18] 2004	Germany	152 patients	18–57	76 in Cineole; 76 in Placebo	47:28 (Cineole); 49:26 (Placebo)	7 days
Tesche [19] 2008	Germany	150 patients	18–65	75 in Cineole; 75 in Herbal preparation similar to Sinupret (BNO 1016)	32:43 (Cineole); 38:37 (Herbal Preparation)	7 days
Gottschlich [17] 2018	Germany	228 patients	18–86	114 in ELOM‐080 (Myrtol); 109 in BNO 1016 (Sinupret)	87:26 (ELOM‐080); 79:30 (BNO 1016)	14 days
Dejaco [21] 2019	Austria/Poland	288	18–81	147 in Tavipec; 141 in Placebo	87:60 (Tavipec); 76:65 (Placebo)	7 days
Pfaar [22] 2022	Germany	463	18–77	233 in ELOM‐080; 230 in Placebo	127:85 (ELOM‐080); 127:81 (Placebo)	14 days

TABLE 3.

Study specific definition of ARS, outcome measures, and reported adverse events.

Authors	Definition of ARS for inclusion in study	Outcomes measures and adverse events
Kehrl [18] 2004	Determination of ARS based on diagnosis from otorhinolaryngological specialist according to clinical findings and symptoms such as headache on bending, sensitivity of pressure points of trigeminal nerve, impairment of general condition, nasal obstruction, rhinological secretion, secretion quantity, secretion viscosity, and frontal headache. Symptom sum score had to be greater than 10 for inclusion in study. Diagnosis of rhinosinusitis was further confirmed by an occipitomental view on B‐scan ultrasonography showing shadowing of the maxillary sinus.	Primary outcome‐change in symptom‐sum score: 4 days: Cineole: −8.6 ± 3.6 Placebo: −3.5 ± 2.8 p < 0.0001 7 days Cineole: −12.5 ± 3.6 Placebo: −6.5 ± 3.5 p < 0.0001 Secondary outcome‐individual symptoms: Significant improvement: Headache on bending, frontal headache, sensitivity of pressure points of trigeminal nerve, impairment of condition, nasal obstruction, rhinological secretion, secretion quantity, and secretion viscosity (p‐values ranged from: < 0.0001 to 0.0010) Secondary outcome‐Rhinoscopic findings: Significant improvement: redness of mucosa, edema, secretion viscosity/quantity, and dryness (p‐values ranged from: < 0.0001 to 0.0228) Adverse events: Cineole: heartburn, and exanthema Placebo: none
Tesche [19] 2008	The diagnosis of ARS was made according to a defined symptom‐sum score which was based on rhinoscopic and clinical signs which are characteristic for rhinosinusitis. The symptom‐sum score includes headache on bending, frontal headache, sensitivity of pressure points of trigeminal nerve, impairment of general condition, nasal obstruction, rhino‐secretion, secretion quantity, secretion viscosity, and fever. Symptom sum score had to be greater than 10 for inclusion in the study.	Primary outcome: change in symptom‐sum score: 4 days: Cineole: ‐6.7 ± 3.4 Herbal preparation: ‐ 3.6 ± 2.8 p < 0.0001 7 days Cineole: ‐ 11.0 ± 3.3 Herbal preparation: ‐ 8.0 ± 3.0 p < 0.0001 Secondary outcome‐individual symptoms: Significant improvement: Headache on bending, frontal headache, sensitivity of pressure points of trigeminal nerve, impairment of condition, nasal obstruction, rhinological secretion, secretion quantity, and secretion viscosity (p‐values ranged from: < 0.0001–0.0010) Adverse events: Cineole: mild GI symptoms Herbal preparation: reflux, headache, nausea
Gottschlich [17] 2018	Participants were diagnosed to have ARS based on the EPOS guidelines [1], which require patients to have two or more of the following symptoms, one of which should be either nasal blockage/obstruction/congestions or nasal discharge. Other symptoms may include facial pain/pressure and reduction or loss of smell.	Rhinosinusitis‐associated‐pain numeric rating scale (NRS): Patient assessment: Facial pain (mean score): ELOM‐080: 0.47 BNO 1016: 0.93 p = 0.0147 Headache (mean difference): ELOM‐080: −5.1 BNO 1016: −4.4 no statistically significant difference Nasal congestion (mean difference): ELOM‐080: −5.3 BNO 1016: −4.9 no statistically significant difference Physician assessment: Tenderness at trigeminus pressure point (mean difference): ELOM‐080: −4.0 BNO 1016: −4.1 no statistically significant difference Sinus percussion pain (mean difference): ELOM‐080: −4.4 BNO 1016: −4.4 no statistically significant difference Assessment of patient satisfaction: Feeling of general illness: ELOM‐080 group more satisfied than BNO 1016 p < 0.05 Physicians global assessment of effectiveness and tolerability: No significant difference Adverse events: ELOM‐080: GI symptoms, dizziness, headache BNO 1016: GI symptoms
Dejaco [21] 2019	Participants were diagnosed to have ARS based on the EPOS guidelines [1].	Major symptom score: 4 days Tavipec: 4.96 Placebo: 5.47 No statistically significant difference 7 days Tavipec: 2.52 Placebo: 3.55 p = 0.0001 Secondary outcome‐individual symptoms: Significant improvement: Nasal obstruction, rhinorrhoea, sinus headache (Tavipec compared to placebo: p‐values ranged from: < 0.001 to 0.05). Postnasal drip (Placebo compared to Tavipec: p < 0.01) Change in Sino‐Nasal Outcome Test (SNOT‐22) 7 days Tavipec: −37.09 Placebo: −27.53 p = 0.001 Global Assessment Scale for Quality of Life: Tavipec: 1.60 Placebo: 3.04 p < 0.0001 Adverse Event: Tavipec: mild GI symptoms Placebo: none
Pfaar [22] 2022	Diagnosis of ARS was based upon EPOS criteria with the severity of the 5 main symptoms for ARS: rhinorrhea (anterior discharge), postnasal drip, nasal congestion, headache, and facial pain/pressure For inclusion in the study, severity had to range between 8 to 12 points, based on a verbal rating scale ranging from 0 to 3 for each symptom.	Major Symptom Score(MSS INV ): 7 days ELOM‐080: 4.3 ± 0.2 Placebo: 4.9 ± 0.2 p = 0.016 14 days: ELOM‐080: 1.1 ± 0.1 Placebo: 1.6 ± 0.1 p = 0.014 Major Symptom Score(MSS PAT ): 14 days: ELOM‐080: 1.7 ± 0.2 Placebo: 2.05 ± 0.2 p = 0.003 Olfactory Function (Snifin’ Sticks Test) 14 days: ELOM‐080: +1.67 Placebo: +1.63 No statistically significant difference Change in Sino‐Nasal Outcome Test (SNOT‐20) 14 days ELOM‐080: 6.0 ± 0.8 Placebo: 8.0 ± 0.8 No statistically significant difference Adverse Event: ELOM‐080: mild GI symptoms Placebo: none

3. Results

3.1. Study Population

The 5 studies selected for review represented 1281 acute rhinosinusitis patients, with the average age of study participants ranging from 30 to 43 years old [17, 18, 19, 21, 22]. No one under the age of 18 years was included in any of the studies reviewed. All studies required a clinical diagnosis of acute sinusitis by an otolaryngologist. The studies evaluated the effects of cineole versus placebo [18], cineole versus an herbal formulation similar to Sinupret [19], ELOM‐080 (active ingredient in Myrtol) versus BNO 1016 (tradename: Sinupret) [17], Tavipec versus placebo [21], and ELOM‐080 versus placebo [22]. A description of these compounds is provided in the following paragraph.

All studies excluded patients with signs of bacterial sinusitis and patients treated with antibiotics. Symptoms highly suggestive of bacterial rhinosinusitis include purulent secretions, severe local facial pain, fever > 38°C, increased CRP/ESR, and a double sickening [1]. The only concomitant treatment used in the studies was xylometazoline, used in Kerhl et al. [18] and Tesche et al. [19]. Kerhl et al. [18] had all patients utilize xylometazoline spray, while Tesche et al. [19] evenly split the use of xylometazoline between two groups tested.

3.2. Intervention: Essential Oils

3.2.1. Cineole

1,8‐Cineole is a component of eucalyptus essential oil and is available as an enteric‐coated capsule under the trade name Soledum [24]. 1,8‐Cineole exhibits antimicrobial activity towards viruses and fungi and has shown weak antibacterial activity [14, 15]. The compound has also exhibited anti‐inflammatory properties [25, 26, 27]. Additionally, 1,8‐cineole was shown to have mucolytic effects, accelerating mucociliary clearance [28, 29, 30].

3.2.2. Myrtol (ELOM‐080)

Myrtol (ELOM‐080) is an oral capsule composed of four essential oils (eucalyptus oil, sweet orange oil, myrtle oil, and lemon oil), and contains 1–8 cineole as a main active ingredient. Myrtol is reported to have anti‐inflammatory, antioxidative, secretolytic, secretomotor, and mucolytic properties [31].

3.2.3. Sinupret (BNO 1016)

Sinupret (BNO 1016) is oral‐enteric consisting of five herbal drugs: Sambuci flos (elderflower), Primulae flos (primula flower), Rumicis herba (sorrel), Verbenae herba (common vervain), and Gentianae radix (gentian root) in a ratio of 1:3:3:3:3, respectively [32]. Sinupret has shown antimicrobial, antiviral, secretolytic, and anti‐inflammatory properties [33, 34].

3.2.4. Tavipec (Spicae Aetheroleum)

Tavipec (Spicae aetheroleum) is a phytomedicine obtained via steam distillation of the flowering tops of Lavandula latifolia [21]. The main components of Spicae aetheroleum are the monoterpenes linalool, 1,8‐cineole, and camphor in concentrations of 34%–50%, 16%–39%, and 8%–16%, respectively [21]. Spicae aetheroleum is known to have mucolytic, anti‐inflammatory, and spasmolytic activity [35].

3.3. Comparisons and Patient‐Reported Outcomes

3.3.1. Cineole Versus Placebo

Kehrl et al. [18] investigated the therapeutic effectiveness of cineole compared to a placebo in 152 patients with acute rhinosinusitis. Patients received two capsules of cineole 100 mg or placebo three times daily for 7 days. Xylometazoline was also used three times daily in all patients. Outcome measures for this study were:

Symptom‐sum score: Score based on the presence and severity of the following clinical findings: 1) headache on bending, 2) frontal headache, 3) sensitivity of pressure points of trigeminal nerve, 4) impairment of general condition, 5) nasal obstruction, 6) rhinological secretion, 7) secretion quantity, 8) secretion viscosity, and 9) fever. For the first 8 clinical findings, a score of 0 was assigned for no symptoms, 1 for slight, 2 for moderate, and 3 for strong/severe. If fever was present, 1 point was added.

Rhinoscopy findings: Score given based on 1) redness of mucosa, 2) edema, 3) secretion viscosity, 4) secretion quantity, and 5) dryness. These rhinoscopy findings were scored as a 0 (nothing), 1 (slight), 2 (moderate), or 3 (strong/severe).

Maxillary Sinus Shadowing: Score given based on B‐scan ultrasonography readings of maxillary sinus shadowing. Score of 0 was assigned for no shadowing, 1 for slight, 2 for moderate, and 3 for marked.

Inflammatory Process: Number of patients with bronchitis, pharyngitis, tracheitis, or conjunctivitis, level of C‐reactive protein, leukocyte count, and erythrocyte sedimentation rate.

Significant improvement in symptom‐sum score was seen with the cineole compared to placebo after 4 days (Mean Δ symptom‐sum score: −8.6 ± 3.6 for cineole versus −3.5 ± 2.8 for placebo) and 7 days (−12.5 ± 3.6 for cineole versus −6.5 ± 3.5 for placebo) (p < 0.0001). Marked improvement was seen in the following single symptoms: headache on bending, frontal headache, sensitivity of pressure points of trigeminal nerve, impairment of condition, nasal obstruction, rhinological secretion, secretion quantity, and secretion viscosity.

There was significant improvement in rhinoscopy findings in the cineole treatment arm, including redness of mucosa (p < 0.0001), edema (p < 0.0001), secretion viscosity (p < 0.0001), secretion quantity (p < 0.0001), and dryness (p < 0.0228). After 7 days of treatment, patients treated with cineole showed significant improvement in maxillary sinus shadowing, which determines the presence of fluid levels. Cineole also showed a marked reduction in inflammatory processes, with a significant decrease in the number of patients with bronchitis (p = 0.0036) and the level of C‐reactive protein (p = 0.0327).

3.3.2. Cineole Versus Sinupret (BNO 1016)

Tesche et al. [19] compared the efficacy of cineole to an herbal compound with a similar composition as Sinupret. 150 patients with acute rhinosinusitis received two 100 mg tablets of placebo and cineole or placebo and the herbal compound three times daily for seven days. Optional treatment with xylometazoline was documented in 90 of 150 patients (45 in the cineole and 45 in the phyto‐compound group). Outcome measures for this study were:

Symptom‐sum score: as defined previously.

Rhinoscopy findings: Score given based on 1) redness of mucosa, 2) edema, and 3) dryness. These rhinoscopy findings were scored as a 0 (nothing), 1 (slight), 2 (moderate), or 3 (strong/severe).

Maxillary Sinus Shadowing: Score of 0 was assigned for no shadowing, 1 for slight backplate echo, 2 for moderate backplate echo on one side, 3 for moderate backplate echo on both sides, and 4 for distinct backplate echo on both sides.

Inflammatory Process: Number of patients with bronchitis.

The symptom‐sum scores were significantly reduced in both treatment groups on days 4 (herbal compound Δ baseline: −3.6 ± 2.8; cineole Δ baseline: −6.7 ± 3.4) (p < 0.0001) and 7 (herbal compound Δ baseline: −8.0 ± 3.0; cineole Δ baseline: −11 ± 3.3) (p < 0.0001). In addition, there was a significantly greater reduction in all individual symptom‐sum score measured outcomes (p < 0.001). Significant improvement in redness of mucosa (p < 0.0001), edema (p < 0.0001), and dryness (p = 0.0002) were also observed. B‐scan ultrasonography after day 7 showed decreased mucosal shadowing (p < 0.0001). Notably, B‐scan ultrasonography is a validated measure, but not included within the current 2015 American Academy of Otolaryngology‐Head and Neck Surgery guidelines [36].

3.3.3. ELOM‐080 (Myrtol) Versus BNO 1016 (Sinupret)

Gottschlich et al. [17] compared the effectiveness of ELOM‐080 to BNO 1016 in the treatment of 223 patients with acute rhinosinusitis over a period of 14 days. Outcome measures for this study were:

Acute Rhinosinusitis Symptoms: Rated using a numeric grading scale, with 0 indicating “no symptoms” and 10 indicating “worst severity imaginable”, for the following items: 1) facial pain when bending forward, 2) headache, 3) nasal congestion, 4) tenderness at trigeminal nerve, and 5) sinus percussion pain.

Patient Satisfaction: Rated on a 5‐point Likert Scale, with 0 indicating “very dissatisfied” and 4 indicating “very satisfied”, for the following items: 1) relief of symptoms, 2) improvement in feeling of general illness, 3) general tolerability, and 5) gastrointestinal tolerability.

Physician's global assessment: Assessed via verbal rating scale (VRS), with 0 indicating “very good” and 3 indicating “very bad”, for the following items: 1) effectiveness and 2) tolerability.

ELOM‐080 demonstrated faster improvement of facial pain starting on day 3 of treatment, with more pronounced relief by the end of treatment (p = 0.0147). Symptom scores for headache and nasal congestion did not show significant differences in improvement between treatment arms. However, there was an improvement in feelings of general illness in patients treated with ELOM‐080 compared to BNO 1016 (p < 0.05).

3.3.4. Tavipec Versus Placebo

Dejaco et al. [21] investigated the therapeutic effectiveness of Tavipec compared to placebo in 288 patients with acute rhinosinusitis. This trial administered two capsules of Tavipec 150 mg or placebo three times daily for 7 days. Outcome measures for this study were:

Major Symptoms Score (MSS): Sum of the following symptoms: 1) nasal obstruction, 2) rhinorrhea, 3) post‐nasal drip, 4) sinus headache, and 5) facial pain, each rated from 0 to 3 (0 = none, 1 = slight, 2 = moderate, 3 = severe).

Sino‐Nasal Outcome Test (SNOT‐22): patient‐reported outcome measure for rhinosinusitis based on 22 items. Severity of symptoms rated on a 6‐point (0–5) Likert scale.

Quality of Life: Verbal rating of 0–10 with 0 indicating “not troublesome” and 10 indicating “worst thinkable troublesome”. Scores from 0 to 3 were interpreted as mild, scores from 4 to 7 were interpreted as moderate, and scores from 8 to 10 were interpreted as severe.

On day 8, the Tavipec group had a significantly lower MSS compared to the placebo group (2.52 vs. 3.55; p = 0.001). The following single symptoms were significantly reduced in the Tavipec group compared to the placebo group: nasal obstruction (p < 0.001), rhinorrhoea (p < 0.05), and sinus headache (p < 0.001). Inversely, postnasal drip was significantly improved in the placebo group compared to the Tavipec group (p < 0.01).

Quality of life was better in the Tavipec group compared with the placebo group (1.60 vs. 3.04, p < 0.001). On day 8, the mean reduction in the SNOT‐22 scores for the Tavipec group was 37.09 vs. 27.53 for the placebo group (p < 0.001). Final SNOT‐22 scores for the two groups were 9.49 and 15.03 (p = 0.002) for the Tavipec group and placebo group, respectively.

3.3.5. ELOM‐080 (Myrtol) Versus Placebo

Pfaar et al. [22] investigated the therapeutic effectiveness of ELOM‐080 compared to a placebo in 463 patients with acute rhinosinusitis. This trial administered four capsules of ELOM‐080 (300 mg) or placebo daily for 14 days. Outcome measures for this study were:

Major Symptoms Score (MSS): as defined earlier. Assessed by the investigator(MSS_INV) and patient(MSS_PAT) separately.

Sino‐Nasal Outcome Test (SNOT‐20): patient‐reported outcome measures for rhinosinusitis based on 20 items.

Olfactory Function (12 item Sniffin’ Sticks): 11 or 12 correct answers indicate normosomnia. 10 or less correct answers indicate hyposmia/anosmia.

Viral Load: determined from paired nasal swabs collected from patients.

MSS_INV at day 7 was significantly lower in the ELOM‐080 group compared to the placebo group (4.3 vs. 4.9; p = 0.016). On day 14, MSS_INV for the ELOM‐080 group remained significantly lower than the placebo group (1.1 vs. 1.6; p = 0.014). The MSS_PAT became significantly lower in the ELOM‐080 group compared with the placebo group (p = 0.012) by day 4 of treatment and remained significantly lower throughout the rest of the experiment.

There was no significant difference between the ELOM‐080 group and the placebo group in the improvement of olfaction (p = 0.19). There was also no significant difference in changes to SNOT‐20 scores between the ELOM‐080 group and the placebo group. Finally, significant changes in viral load were seen between the ELOM‐080 treated group and the placebo group on day 3. Patients treated with ELOM‐080 had a decrease in viral load from baseline, whereas patients treated with placebo had an increase in virus from baseline (p = 0.043).

3.3.6. Adverse Results

Adverse drug reactions induced premature discontinuation of treatment in three patients using BNO 1016 and one patient using ELOM‐080 [17]. The most common adverse side effect reported were gastrointestinal symptoms such as stomach cramps, nausea [17, 18, 19, 21, 22], heartburn, exanthema [18], reflux [19], and headache [17, 18, 19]. Overall, the side effects listed across all studies appeared to be mild, rarely interfered with treatment, and did not require additional intervention.

4. Discussion

This systematic review evidences the paucity of literature assessing the efficacy of essential oils in the treatment of acute rhinosinusitis. Overall, the evidence suggests that 1,8‐cineole provides alleviation of symptoms in acute rhinosinusitis in comparison to placebo treatments and herbal medicines, such as Sinupret Extract CT or BNO 1016 [17, 18, 19]. Additionally, Myrtol, which is the tradename of ELOM‐080 and contains 1,8‐cineole as the primary active component, achieved faster relief of facial pain in comparison to BNO 1016 [17]. Pfaar et al. [22] also demonstrated the superiority of Myrtol compared to placebo in alleviation of rhinosinusitis symptoms. In addition to cineole and Myrtol, Tavipec significantly improved rhinosinusitis symptoms compared to placebo [21].

Unfortunately, inconsistencies between chosen outcome measures and symptom grading scales make comparisons between study data difficult. Kehrl et al. [18] and Tesche et al. [19] used the same symptom‐sum score to measure acute rhinosinusitis severity (Table 3). While the symptom‐sum score used is not a validated measure for diagnosis, a guideline for clinical trials on rhinosinusitis published a total symptom score that was similar to these studies [18, 19, 37]. The validated scoring system featured a Likert scale scoring system that rated symptoms from zero (no symptoms) to six (very severe symptoms). Symptoms assessed included: nasal obstruction/blockage/congestion, discolored nasal drainage, facial pain/pressure/fullness, headache, fatigue, decreased sense of smell, ear pain/pressure/fullness, cough, halitosis, dental pain, and fever. Both Kehrl et al. [18] and Tesche et al. [19] assessed similar symptoms but excluded fatigue, sense of smell, ear pain, cough, halitosis, and dental pain. While the guideline assessed for generalized headache, Kehrl et al. [18] and Tesche et al. [19] looked more specifically at frontal headache and headache on bending.

Gottschlich et al. [17] employed a slightly different symptom grading scale from Kehrl et al. [18] and Tesche et al. [19]. Compared to the symptom sum score used in Kehrl et al. [18] and Tesche et al. [19], the Gottschlich et al. [17] grading scale added assessment for sinus percussion pain and omitted assessment for impairment of general condition, nasal obstruction, rhinological secretion, quantity and viscosity of secretion, and fever. Symptom grading scales for Kehrl et al. [18], Tesche et al. [19], and Gottschlich et al. [17] also differed slightly from the symptom grading scales of Dejaco et al. [21] and Pfaar et al. [22]. Compared to the Symptom Sum Score used in Kehrl et al. [18] and Tesche et al. [19], the Major Symptoms Score used by Dejaco et al. [21] and Pfaar et al. [22] added assessment for post‐nasal drip and omitted evaluation of headache on bending, impairment of general condition, rhinological secretion quantity/viscosity, and fever.

We believe a more standardized approach to measuring improvements in acute rhinosinusitis symptoms, such as the scoring system proposed by Meltzer et al. [37], needs to be implemented in prospective reviews going forward to facilitate easier comparison between results.

5. Limitations

Kerhl et al. [18] and Tesche et al. [19] allowed the concomitant use of xylometazoline spray for relief of nasal congestion. Kerhl et al. [18] had all patients utilize xylometazoline spray, while Tesche et al. [19] had 90 of 150 patients utilize it. However, the 90 patients were split evenly between the two treatment groups, minimizing potential confounding of results. Additionally, much of the literature on essential oils and rhinosinusitis is published in either German or Russian, and thus was not included in this study.

6. Conclusion

Overall, this review highlights a lack of comprehensive research on the effectiveness of essential oils for acute rhinosinusitis. However, evidence suggests that 1,8‐cineole, an active component of Myrtol, offers superior symptom relief when compared to placebo and some herbal medicines. Despite promising results, diagnostic and symptom assessment methods vary across studies, making it difficult to compare findings. A more standardized approach to symptom measurement is recommended for future research.

Conflicts of Interest

The authors declare no conflicts of interest.

Matl C. M., Jang W., Salley J. R., et al., “Effects of Essential Oils in the Treatment of Acute Rhinosinusitis: A Systematic Review,” Laryngoscope Investigative Otolaryngology 10, no. 3 (2025): e70189, 10.1002/lio2.70189.

Data Availability Statement

Data sharing is not applicable to this article as no new data were created or analyzed in this study.