Carbamazepine is an anticonvulsant that is being used more frequently in the treatment of various psychiatric disorders. The drug has been associated with serious adverse reactions that appear to have an immunological pathogenesis. A case report describing a patient suffering an adverse reaction to carbamazepine is presented, to illustrate the various body systems typically affected in the apparent hypersensitivity reaction. The importance of laboratory and patient monitoring during the initial 3 months of carbamazepine therapy is reinforced.