The involvement of the neurological system in epidemic dropsy is controversial. During two outbreaks of epidemic dropsy, detailed neurological and ocular examinations and electrophysiological studies of peripheral nerves and muscles (motor nerve conduction velocities, sensory nerve latencies and electromyography) and eye (electroretinogram and visually evoked cortical responses) were therefore undertaken. Amongst the 239 subjects examined, burning sensation and tingling paraesthesias of feet were reported by 42.3 and 35.6%, respectively; but none had any objective evidence of central or peripheral nervous system involvement. Electrophysiological studies of peripheral nerves and muscles (10 cases with subjective manifestations) and eyes (24 eyes of 12 patients hospitalized for control of glaucoma) were essentially normal. It is concluded that Argemone mexicana or its toxins do not have any significant effect on the nervous system.