Table 2.

Clinical trials evaluating the efficacy of various natural products in relieving the symptoms of xerostomia.

Natural Product/Compound	Product Form	Number of Patients	Outcome/Results	Year of Publication	Reference
Camellia sinensis (L.)	Camellia sinensis (L.) (green tea) extract lozenge	60	The green tea extract lozenge showed a statistically significant increase in both SWSFR and UWSFR, but no significant difference in the quality of life (QoL).	2014	[41]
Thymus L.	Thyme honey	72	Thyme honey was found to be effective in reducing or stabilizing the degree of xerostomia, and also positively affected other symptoms, such as pain, taste loss, dysphagia (difficulty swallowing), QoL, and general satisfaction. Dose: Oral rinses (20 mL of thyme honey diluted in 100 mL of purified water).	2017	[42]
Vaccinium vitis-idaea L. (Common name: lingonberry)	Fermented lingonberry juice (FLJ) (Lingora®, Vantaa, Finland)	21	FLJ mouthwash positively affected all five salivary parameters (resting and stimulated saliva secretion rates, resting saliva pH, and stimulated saliva buffering capacity), with statistically significant improvements. Dose: 10 mL daily for 30 s.	2022	[43]
Cocos nucifera L. (Common name: coconut)	Coconut oil	30	There was no significant difference in xerostomia quality of life scale (XeQoLS) scores pre- and post-treatment among the entire study group and participants who continued coconut oil beyond the study period. Dose: Coating patient’s mouth with coconut oil prior to meals and at bedtime.	2020	[44]
Lycopene enriched Olea europaea L. (olive)	Lycopene enriched olive oil spray	60	Patient-assessed benefits and satisfaction with the spray were higher in the treatment group but the difference between treatment and placebo groups was not statistically significant. Dose: 1.5 mL spray to the mouth, three times per day.	2017	[45]
Zingiber officinale Roscoe (Common name: ginger)	Ginger ethanolic extract in a form of oral spray	20	The ginger herbal spray effectively increased salivation and reduced the severity of dry mouth in patients with type II diabetes.	2017	[46]
Zingiber officinale Roscoe (Common name: ginger)	Ginger capsule (Zintoma, Goldaru Company, Iran)	61	Marginally significant improvement in xerostomia symptoms with ginger treatment. Still, there were no significant differences between the groups regarding improvement of dry mouth symptoms and quality of life issues, except for dry mouth experience throughout the day. Dose: three capsules daily.	2017	[47]
Zingiber officinale Roscoe (Common name: ginger)	Ginger mouthwash (25% ginger)	105	Ginger mouthwashes significantly reduced all xerostomia symptoms (need to drink water to swallow dry foods, decreased salivation, mouth dryness upon waking, dry mouth during travel, and burning mouth sensation. Dose: 20 mL three times daily for 14 consecutive days.	2021	[48]
Aloe vera (L.) Burm.f. (Common name: Aloe vera)	Aloe vera mouthwash (50% aloe vera)	105	Aloe vera mouthwashes significantly reduced all xerostomia symptoms (need to drink water to swallow dry foods, decreased salivation, mouth dryness upon waking, dry mouth during travel, and burning mouth sensation. Dose: 20 mL three times daily for 14 consecutive days.	2021	[48]
Aloe vera (L.) Burm.f. and Mentha L. (Peppermint)	Moisturizing gel (Veramin)	80	The results indicated that the gel (Veramin) had significant effects on reducing mouth dryness and improving oral health. Dose: Apply gel to all surfaces of the oral mucosa, the gum, and the tongue after brushing, every 4 h.	2018	[49]
Glucosylceramide	Tablets containing Glucosylceramide Extracted from Ananas comosus (L.) Merr. (Common name: Pineapple) (GCP)	16	GCP administration significantly increased the oral moisture level of the lingual mucosa and the visual analog scale value related to xerostomia. Dose: one tablet per day (1.2 mg GCP per tablet).	2019	[50]
Linum usitatissimum L. (also known as linseed)	Linseed extracts: Salinum by Camurus AB, Sweden and MAS-84	20	Both tested preparations had a beneficial effect on dry mouth symptoms, with Salinum showing improved results and performance. Dose: 2 mL.	1995	[51]
Matricaria chamomilla L. (Common name: Chamomile) and Linum usitatissimum L. (also known as linseed)	Chamomile and linseed saliva substitute	74	The chamomile and linseed saliva substitute positively affected four out of five xerostomia symptoms, while the conventional saliva substitute only impacted two of them. Dose: 2 mL, four times per day.	2017	[52]
Hibiscus sabdariffa	Aqualief™ (Helsinn Healthcare SA, Lugano, Switzerland) tablets	60	Aqualief™ significantly improved dry mouth symptoms compared to the placebo (normalizing saliva pH and significantly increase the saliva flow rate). Dose: Three times/day (after meals) for six consecutive days.	2020	[53]
Malva sylvestris L. and Alcea digitata (Boiss.)	Malva sylvestris and Alcea digitata in powdered form	62	The experimental and control groups revealed a significant decrease in the visual analog scale (VAS) score for the experimental group at four weeks when compared to the control group. Dose: Three times per day for four weeks.	2016	[54]
Vitamin C/E Complex	Antioxidant supplements	45	Short-term supplementation with an antioxidant vitamin E/C complex protects against RT-induced xerostomia in patients with head and neck cancer. Dose: Twice per day.	2016	[55]
Plantago ovata Forssk.	Plantago ovata husk in water as mouthwash	28	The herbal compound significantly mitigated oral mucositis, pain, xerostomia, and improved life quality versus placebo (p < 0.05); the oral care protocol likewise reduced oral mucositis. Dose: Three times per day.	2020	[56]
Pilocarpine	Oral tablets (systemic administration)		Systemic administration of pilocarpine increases resting and stimulated salivary flow, decreases subjective oral dryness, and improves chewing and speaking abilities of patients. Dose: Ranging from 2.5 to 10 mg, taken orally three or four times daily	2022	[12]