It has been well accepted that the nonsteroidal antiinflammatory drugs (NSAID) can cause upper gastrointestinal (GI) blood loss and reactivation of peptic ulcer disease. This report describes 3 patients in whom the ingestion of a NSAID was temporally associated with serious lower GI disease, including bleeding in 2 patients. These cases suggest an association between NSAID and activation of serious lower GI disease.