Purpose: To determine the laboratory and clinical efficacy of lavender oil in the treatment of recurrent aphthous ulceration (RAU).
Methods: This was a randomized double-blind, placebo-controlled study performed firstly to treat the induced ulcers by different methods in experimental animals (rabbits) treated with lavender oil or placebo. Clinical and histological healing was established by measuring the area of the ulcer and inflammation levels in each test group. Secondly, safety/toxicity; the median lethal dose (LD50) was studied in albino mice, and dermal irritation test was performed by primary irritation to the skin and measured by a patch-test technique on the intact skin of the albino rabbit. Thirdly, antibacterial effect; lavender oil was screened against bacteria obtained from swab specimen of human subjects' RAU using disc diffusion method. Fourthly, clinical study; 115 subjects (mean age 38 years, mean weight 75 kg) were divided into two groups of subjects topically treated with lavender oil or placebo. The clinical efficacy was assessed by inflammation level, erythema, edema, ulcer duration, ulcer size, mean area under the curve of ulcer area, healing time, and associated pain intensity and reduction.
Results: Animals treated with lavender oil showed a significant ulcer size reduction, increased rate of mucosal repair, and healing within 3 days of treatment compared to baseline and placebo groups [2-3 days (90%), 4 days (10%)] (P=0.001). The intraperitoneal LD50 value in mice was 6.5 gm/kg; clinical dermal irritation test showed no sign of irritation in the tested products. Lavender oil showed a broad antibacterial activity against all tested strains; it exhibited significant inhibition on tested bacteria where the value of zone of inhibition ranged from 14.5-24 mm vs Streptomycin (25 microg/disc) 12-22 +/- 0.5 mm; MIC was > 6.4-36 mg/ml. RAU patients treated with lavender oil showed a significant reduction in inflammation level, ulcer size, healing time, from 2-4 days [2 days (40%), 3 days (50%), 4 days (10%)], and pain relief mostly from the first dose, compared to baseline and placebo. No side effects were reported.