Two hundred cases with recurrent idiopathic headache and 200 age- and sex-matched controls without headaches were compared for the occurrence of medical problems and diagnoses according to their primary physicians. Hypertension, vertigo and dizziness, peptic ulcer, gastroesophageal reflux and depression and/or anxiety were among diagnoses seen more frequently in the headache cases, while nephrolithiasis, excessive ethanol use and abdominal pain in women were more common in the controls. There were no significant differences between the two groups in the diagnosis of cardiac disease, including mitral valve prolapse and ischemic heart disease, and occlusive cerebrovascular disease. Possible underlying mechanisms are discussed. These findings need confirmation and further investigation.