A phthous ulcers are among the most common oral lesions in the general population, with a frequency of 5-25% and threemonth recurrence rates as high as 50%. 1 Aphthous ulcers have been reported in 2-4% of HIV-seropositive patients, although these patients suffer from larger and more frequent aphthae in advanced stages of their disease. 2 Aphthous ulcers are often quite painful; may lead to difficulty in speaking, eating, and swallowing; and may negatively affect patients' quality of life. 2,3 In patients with advanced HIV disease, aphthous ulcers may exacerbate weight loss. While most aphthae are small and heal within 7-10 days, larger ulcers can persist for weeks or months. Consequently, therapy for the disease of recurrent aphthous ulcers (RAU) should address both healing and the prevention of new ulcers. This article reviews the clinical features and etiology of RAU in HIVseropositive and HIV-seronegative persons; the mechanisms of action, efficacy, and safety of medications used to treat RAU; and the recommended therapeutic strategies. The studies that provided the basis for