Recurrent aphthous stomatitis (RAS) is a common, painful, and ulcerative disorder of the oral cavity of unknown etiology. No cure exists and medications aim to reduce pain associated with ulcers through topical applications or reduce outbreak frequency with systemic medications, many having serious side effects. The purpose of this pilot study was to evaluate the potential of a product to reduce the number of outbreaks of RAS ulcers. Propolis is a bee product used in some cultures as treatment for mouth ulcers. In this randomized, double-blind, placebo-controlled study, patients were assigned to take 500 mg of propolis or a placebo capsule daily. Subjects reported a baseline ulcer frequency and were contacted biweekly to record recurrences. Data were analyzed to determine if subjects had a decrease of 50% in outbreak frequency. The data indicated a statistically significant reduction of outbreaks in the propolis group (Fisher's exact test, one sided, p = 0.04). Patients in the propolis group also self-reported a significant improvement in their quality of life (p = 0.03). This study has shown propolis to be effective in decreasing the number of recurrences and improve the quality of life in patients who suffer from RAS. Propolis should be evaluated further in a larger sample clinical trial.