Study type: Human study
DOI: 10.1186/s12906-026-05640-8
Related subjects
- Centella asiatica
Introduction
At Chiang Mai University in Thailand, a double-blind clinical trial published 21 October 2026 tested a 0.12% Centella asiatica leaf-extract mouthwash after removal of an impacted lower wisdom tooth. In 36 participants, wound healing, pain and facial swelling were not significantly better than with placebo.
On this page
Study card: where and when?
Country: Thailand; city: Chiang Mai; clinical site: Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Chiang Mai University. Researchers from the university’s oral biology/oral pathology and pharmaceutical sciences departments also contributed. Type: randomized, double-blind, placebo-controlled human clinical trial; published: 21 October 2026 in BMC Complementary Medicine and Therapies; DOI: 10.1186/s12906-026-05640-8. Trial registry: TCTR20250909004, registered 9 September 2025; ethics approval 29/2025. [1]
Why was the trial conducted?
Centella contains constituents including asiaticoside, madecassoside, asiatic acid and madecassic acid that have attracted experimental interest in inflammation and wound repair. Laboratory mechanisms do not establish that a preparation improves patient outcomes. The question here was whether this particular mouthwash, added to routine postoperative care, improved healing or reduced symptoms.
Participants and intervention
Recruitment and follow-up took place from September 2025 to March 2026; 36 people aged 18–35 undergoing surgery for an impacted lower third molar were analyzed: 17 received Centella mouthwash and 19 placebo. Participants with certain systemic illnesses, active infection, pregnancy or breastfeeding, relevant allergies and regular herbal-supplement use were excluded. The planned recruitment was 40; enrollment ended at 36 for logistical assay capacity rather than interim efficacy findings. [1]
The commercial C. asiatica leaf extract had been prepared by extraction with 70% ethanol at 80–90°C for three hours. Researchers placed 3.60 g of extract in 3.0 L of mouthwash base, yielding 0.12% w/v. The base contained glycerin, xylitol, sodium chloride and preservatives; the matched placebo used the same base without Centella. Participants rinsed 15 mL for 30 seconds twice daily for seven days, beginning the day after surgery. These are experimental specifications, not instructions to compound or use a home remedy. All participants also received standard care, including amoxicillin 500 mg three times daily for five days, ibuprofen 400 mg three times daily for three days and optional paracetamol. [1]
What was measured?
The primary endpoint was the oral wound-healing category on day 7: good, acceptable or poor. Secondary endpoints were pain at rest and with maximum mouth opening at 6–120 hours, facial swelling, and salivary FGF-2 and VEGF-A measured before surgery and on day 4.
Wound healing: numerical differences, no statistical proof
With Centella, good/acceptable/poor healing occurred in 7/17 (41.2%), 8/17 (47.1%), 2/17 (11.8%); with placebo it occurred in 4/19 (21.1%), 15/19 (78.9%), 0/19. Despite the higher numerical fraction classified good in the treatment group, the prespecified three-category analysis gave p=0.105, not statistically significant. An exploratory good-versus-other analysis gave RR=1.96, 95% CI 0.69–5.53, p=0.281; the interval is too wide to establish a benefit. Failure to detect significance is also not proof that no benefit is possible in every setting. [1]
Pain, swelling and salivary biomarkers
Pain decreased over time in both groups, without a significant treatment effect at rest (p=0.661) or during maximum mouth opening (p=0.856). No significant between-group swelling difference was found. After baseline adjustment, salivary FGF-2 geometric mean ratio=0.54 (95% CI 0.27–1.10; p=0.088) and VEGF-A=0.71 (95% CI 0.48–1.04; p=0.075), neither significant. These exploratory biomarker differences must not be presented as proof of improved tissue repair. [1]
Safety and limits
A few mild, transient oral symptoms occurred; no serious events or discontinuations were reported over seven days. That does not establish long-term safety or exclude uncommon harms. Strengths include randomization, placebo control, blinding, preregistration and standardized surgery by one surgeon. Limitations include the small sample, short follow-up, early logistical stop, no formal blinding-success test, wound assessment by one rater and lack of participant-level rescue paracetamol quantification. Only this mouthwash formulation was studied; results do not automatically apply to Centella tea, capsules, skin creams or other wounds.
A common claim—what do the findings say?
Claim: Because Centella is linked to wound healing, its mouthwash speeds healing after wisdom-tooth surgery. Verdict: Not demonstrated in this trial. Plausible laboratory mechanisms cannot replace a reliable clinical difference. [1]
Funding and conclusion
The Faculty of Dentistry Research Fund at Chiang Mai University supported the study; the authors said the funder had no role in design, data handling or manuscript preparation and declared no competing interests. Overall, 0.12% Centella mouthwash did not show a statistically significant improvement in wound healing, pain or swelling after lower wisdom-tooth surgery in this small trial. It should not replace usual postoperative care.
Important note
The 0.12% leaf-extract mouthwash was studied for seven days alongside standard postoperative treatment; do not improvise a home formulation or replace prescribed care. A small short trial without serious events cannot establish long-term safety. Findings for mouthwash do not generalize to oral supplements, teas, creams or other types of wounds.
This article provides educational information and does not replace advice from a qualified healthcare professional.
Sources and references
- Effect of Centella asiatica extract mouthwash on oral wound healing following mandibular third molar surgery: Randomized controlled trial · Read source — BMC Complementary Medicine and Therapies