This is a prospective, randomized, blinded, placebo-controlled, crossover clinical trial to evaluate the efficacy of 2-DeNT oral topical powder in the treatment of recurrent aphthous stomatitis (RAS). To be included in the study, subjects must have had minor RAS ulcers of less than 48 hours duration. It was randomly determined which powder was used first; all subjects used both the 2-DeNT powder and the placebo powder. Subjects applied the powder twice daily and maintained a daily log recording the size of the ulcer, its erythema score, and their level of pain. The subjects continued applying the 2-DeNT powder until the ulcer was resolved.