Five cases of the phenytoin syndrome are reviewed here. This hypersensitivity reaction is characterized by fever, eruption, lymphadenopathy, and hepatitis. Anemia, pharyngitis, diarrhea, and nephritis may also be associated. The skin eruption is pleomorphic, presenting as morbilliform eruptions, follicular papules and pustules, erythroderma, or toxic epidermal necrolysis. The management of these patients is made more difficult by the tendency for multiple relapses even after the use of phenytoin has been discontinued.