Phenytoin hypersensitivity syndrome (PHS) is a rare, and important entity characterized by rash, fever, lymphadenopathy, leukocytosis with atypical lymphocytes, eosinophilia and associated hepatitis. In this article, we present the clinical, laboratory and histopathologic results of 5 cases of PHS. In therapy, pheyntoin was stopped and sodium valproate (10-20 mg/kg day) was started. Additionally, prednisolone was given in two patients who had not resolved eruption with conservative therapy.