Recurrent aphthous ulcers (RAU) are the most common oral ulcerative disease, affecting 10% to 20% of the population. There are 3 clinical subtypes-minor, major, and herpetiform. Minor aphthous ulcers are the most common subtype, representing 80% to 90% of all recurrent aphthous ulcers. Clinically, RAU present as extremely painful, shallow ulcerations with an erythematous halo on unattached oral mucosa. The primary differential diagnosis is oral herpes simplex. The etiology of RAU is unknown. Topical corticosteroids are the mainstay of therapy.