The tremorgenic toxin isolated from strains of Aspergillus flavus by Wilson and Wilson in 1964, has recently been identified as an indole-mevalonate metabolite. The toxin, named aflatrem, has a remarkably similar structure to other tremorgenic toxins isolated from toxigenic Claviceps paspali Stevens et Hall cultures, C. paspali ergot, and Penicillium paxilli Bainier. Aflatrem is produced by some sclerotiaforming aflatoxigenic strains of A. flavus, and these strains may thus pose a multiple toxigenic threat.