The clinical features, etiology, and treatment of recurrent aphthous ulcers (RAU) are discussed. Aphthous ulcers are among the most common oral lesions in the general population, with a frequency of up to 25% and three-month recurrence rates as high as 50%. The ulcers, which usually occur on the nonkeratinized oral mucosa, can cause considerable pain and may interfere with eating, speaking, and...