Effect of levamisole on the incidence and prevalence of recurrent aphthous stomatitis. A double-blind clinical trial.

Twenty patients with severe recurrent aphthous stomatitis were treated with a new drug, levamisole, to determine its effects upon the incidence and prevalence of recurrent aphthous stomatitis. The trial, conducted in a non-crossover, double-blind fashion, did not demonstrate any statistically significant differences when levamisole and placebo groups were compared over time either in the number of ulcers, number of ulcer-days, mean duration of ulcers, or mean number of ulcers per day. Positive subjective results were experienced by the 10 patients receiving levamisole but these were not of sufficient magnitude to affect group mean differences.