Autonomic dysfunction in five patients with manganism was investigated by sympathetic skin response (SSR) and RR interval variation (RRIV). A comparison was made with 10 patients with Parkinson's disease (PD) and 10 normal controls. The subjects were age-matched and in PD disease stage-matched.Autonomic symptoms were more common in PD than in manganism. In SSR, the latency was prolonged in PD and manganism, while the amplitude was reduced only in PD. The RRIV was decreased in PD and manganism, but the reduction in RRIV was more severe in PD than in manganism.The present data indicate that autonomic disturbance may occur in manganism, but is less frequent and less severe when compared with PD.