Cyclopiazonic acid was isolated and identified from a sample of kodo millet seed that caused symptoms of 'kodua poisoning' in man. The extract of the toxic grain when injected intraperitoneally into mice produced symptoms of depression and complete loss of mobility. The seed was infected by Aspergillus flavus and A. tamarii and both fungi produced cyclopiazonic acid. This is the first report of the association of a mycotoxin with kodua poisoning and of A. tamarii with mycotoxicoses.