Table 1.

Main characteristics of the studies published on the clinical applications of lemongrass essential oil (LGEO) between 1 January 2013, and 1 November 2022.

Author (Year)	Country and Participants	Study Design	Intervention	Duration of Intervention	Evaluation	Outcome
Satthanakul et al. [41] (2015)	Thailand, 20 healthy volunteers	Double-blinded, randomized, placebo-controlled clinical trial	Group A (n = 10): LGEO (Cymbopogon citratus) mouthrinse 2×/day in the morning and night. Group B (n = 10): placebo mouthrinse 2×/day in the morning and night.	7 days	The concentration of volatile sulphur compounds in breath measured by halimeter. Organoleptic test using a 9-point hedonic scale.	LGEO reduced concentration of volatile sulphur compounds in breath significantly in comparison with placebo both after 1-min once rinse and 7-days treatment. Participants were more satisfied with the LGEO rinse (overall satisfaction taste, breath freshness).
Dany et al. [42] (2015)	India, 60 patients with mild to moderate gingivitis	Double-blinded, randomized, controlled clinical trial	Group A (n = 20): 0.25% LGEO (C. citratus or Cymbopogon flexuosus) mouthwash 2× daily + toothbrushing. Group B (n = 20): 0.2% chlorhexidine mouthwash 2× daily + toothbrushing. Group C (n = 20): toothbrushing only.	21 days (follow-up at 14 and 21 days)	Plaque index (PI) and gingival index (GI) scores	PI and GI improved significantly after 14 and 21 days in all groups. A greater reduction in PI and GI score was recorded in the LGEO group after 14 and 21 days, followed by chlorhexidine mouthwash group, followed by oral prophylaxis only group.
Akula et al. [43] (2021)	India, 60 healthy children between 9–12 years	Single-blinded, randomized controlled trial	Group A (n = 20): 0.25% LGEO (C. citratus) mouthwash 2× daily. Group B (n = 20): 0.2% chlorhexidine mouthwash 2× daily. Group C (n = 20): oral prophylaxis alone, n = 20).	21 days (follow-up after 14 and 21 days)	Plaque pH, plaque index (PI), and gingival index (GI)	Intragroup comparison of PI and GI showed a significant decrease between 14 and 21 days in groups A and B, whereas mean plaque pH increased only in group A at day 21 compared with baseline. Intergroup comparison of the PI scores of the three groups at days 1, 14, and 21 did not show any statistically significant differences, but the mean GI was significantly different among the three groups at days 14 and 21.
Azad et al. [44] (2016)	Germany, 46 patients with moderate chronic periodontitis undergoing scaling and root planing	Double-blinded, randomized, placebo-controlled clinical trial	Group A (n = 23): LGEO (C. flexuosus) mouthrinse 2× daily. Group B (n = 23): placebo mouthrinse 2× daily.	14 days (follow up after 3 and 6 months)	Probing depth (PD), attachment level (AL), bleeding on probing (BOP) and modified sulcus bleeding index (SBI) were measured at baseline, 3 months, and 6 months, and subgingival plaque was assessed for periodontitis-associated bacteria.	AL, PD, BOP, and SBI improved significantly in both groups after 3 and 6 months. AL improved significantly better in the group A after 3 and 6 months. The improvement of BOP was also better in the group A after three months. There was no significant difference between the groups at SBI. Test group had more reduction in Treponema denticola and Fusobacterium nucleatum after 3 months and Tannerella forsythia after 6 months. Prevotella micra and Campylobacter rectus decreased significantly in both groups after 3 months.
Mittal et al. [45] (2022)	India, 40 subjects suffering from chronic periodontitis	Double-blinded, randomized controlled trial	Group A (n = 20): 2% LGEO (C. citratus) gel administered into the periodontal pocket after scaling and root planning. Group B (n = 20): 10% doxycycline hyclate gel administered into the periodontal pocket after scaling and root planning. Both groups were advised to use 0.2% chlorhexidine mouthrinse.	3 months (follow-up after 1 and 3 months)	The clinical assessments of gingival index (GI), plaque index (PI), probing pocket depth (PPD), and clinical attachment level (CAL); colony forming unit (CFU) scores of Porphyromonas gingivalis, Actinomyces naeslundii, and Prevotella intermedia	Both the 2% LGEO gel and 10% doxycycline gel significantly improved clinical mean scores after 1 and 3 months (except PI in the LGEO group) and reduced CFU scores for periodontal pathogens.
Leelapornpisid et al. [46] (2015)	Thailand, 29 healthy volunteers	Double-blinded, placebo-controlled clinical trial	All participants used an LGEO (C. citratus) containing body cream and a placebo cream twice daily on the forearm.	4 weeks	Skin condition was evaluated using the Skin Visiometer and skin moisture was evaluated with the Corneometer® at three test sites (untreated, active-cream, and placebo-cream).	LGEO cream significantly improved surface texture compared to baseline, whereas in case of untreated and placebo-treated surfaces no such effects were observed. Both LGEO cream and placebo improved skin hydration.
Carmo et al. [47] (2013)	Brazil, 96 patients diagnosed with pityriasis versicolor	Safety (I) phase: open clinical trial. Efficacy (II) phase: randomized, open clinical trial.	Phase I: 20 patients used an LGEO (C. citratus) shampoo 3× weekly and an LGEO cream 2× daily. Phase II: Group A (n = 30): LGEO shampoo 3× weekly and an LGEO cream 2× daily. Group B (n = 30): ketoconazole shampoo 3× weekly and a ketoconazole cream 2× daily.	40 days (each phase)	Phase I: adverse reactions Phase II: rate of mycological cure	Phase I showed no adverse events (except one case of burning sensation on the scalp after applying the shampoo). Phase II, LGEO had a 60% mycological cure rate, while ketoconazole had over 80%. Both treatments were effective, however, ketoconazole was significantly more effective.
Chaisripipat et al. [48] (2015)	Thailand, 30 healthy volunteers experiencing dandruff	Double-blinded, randomized, placebo-controlled trial	Group A (n = 10): application of 5 drops of a head tonic containing 5% LGEO (C. flexuosus) in one side of the head and a placebo hair tonic on the other side of the head, 2× daily. Group B (n = 10): application of 5 drops of a head tonic containing 10% LGEO in one side of the head and a placebo hair tonic on the other side of the head, 2× daily. Group C (n = 10): application of 5 drops of a head tonic containing 15% LGEO in one side of the head and a placebo hair tonic on the other side of the head, 2× daily.	14 days (follow-up: 7 and 14 days)	Reduction of dandruff using the D-Squame® scale	The application of LGEO hair tonics with 5, 10, or 15% reduced dandruff significantly (p < 0.005) at day 7 (33, 75, and 51%) and increased the effect even more (p < 0.005) at day 14 (52, 81, and 74%). Placebo treatment was less effective, but also showed significant efficacy in groups B and C after 21 days.