An isolate of F. verticillioides (MRC826) that induced experimental leukoencephalomalacia, also caused acute toxicity when fed to pigs and administered per rumen fistula to sheep. Pigs developed severe pulmonary edema while sheep manifested severe nephrosis and hepatosis. A less toxic isolate (F. verticillioides MRC602) fed to baboons resulted in acute congestive heart failure or hepatic cirrhosis, depending on the dose. Both isolates were toxic to rats and caused hepatic cirrhosis and intraventricular cardiac thrombosis.