From a series of experimental studies with pigs (12–16 kg), either pulmonary edema or liver failure emerged as a distinct pathogenetic expression of fumonisin B₁ (FB₁) toxicosis. The primary determinant as to which pathogenetic consequence developed was the quantity (dose) of the mycotoxin fed or intubated per kilogram of body weight per day. Pigs intubated with a minimum of 16 mg FB₁/kg/day developed severe interlobular edema with or without hydrothorax and variably severe pulmonary edema. Pigs intubated with < 16 mg FB₁/kg/day or pigs fed diets containing 200 mg FB₁/kg of feed developed marked icterus and hepatocellular necrosis. The spectrum of degrees of severity of pulmonary edema observed in the experimental pigs allowed rational speculation regarding evolution of the pathologic changes.