The purpose of this article is to report a case of severe stomatitis in a patient with pediatric epilepsy taking divalproex sodium. The case was reviewed with detailed oral examinations. This 5-year-old child developed severe stomatitis 18 months after institution of divalproex sodium. Cessation of the medication was associated with resolution of the stomatitis. A review of the pertinent literature is also provided. Stomatitis is a rare but potentially serious adverse effect of divalproex sodium administration. (J Child Neurol 2002;17: 225-227).