Several studies have raised the question of abnormal biogenic amine metabolism in Duchenne muscular dystrophy (DMD). A small group of DMD patients and controls were screened for abnormalities in systemic biogenic amine metabolism in a carefully controlled clinical environment The mean 24-hour urinary excretion levels of norepinephrine, epinephrine, and 5-hydroxyindoleacetic acid (5-HIAA) were identical in the group of DMD patients compared to their normal sibling controls. In the cerebrospinal fluid (CSF), 5-HIAA and homovanillic acid (HVA) levels were similar in DMD patients and controls, and no 5-hydroxytryptamine (5-HT) was detected in the CSF of either group. This study suggests that the characteristic lesions of DMD do not result from a simple excess of circulating amines.