Five cases of severe encephalopathy due to chronic ingestion of bismuth have been studied by cerebral computed tomography (CT). In every case, areas of increased attenuation coefficient in the basal ganglia and the cortex of the cerebral hemispheres were demonstrated. These regions of increased attenuation were diffuse with irregular, patchy denser areas. The increased attenuation in the gray matter territories contrasted with decreased attenuation of the white matter, particularly evident in the centrum semiovale of each hemisphere and probably related to edema. Some ventricular dilatation was also present in three cases. In one patient, areas of increased attenuation were demonstrated in the cerebellum. Follow-up CT studies of one patient revealed regression of the pathological findings. This regression accompanied the clinical improvement, which, in every case, followed the termination of the bismuth intake.