A case of ergotism is described in a patient with Banti's syndrome in whom a porto-systemic shunt had been made three times. She was admitted to hospital with severe ischaemia of the extremities after having taken a single oral dose of 1 mg ergotamine tartrate. Her condition improved rapidly after 2 to 3 days and the circulation was normal after one week. The possible mechanism of ergotism in this patient is discussed. Although the plasma concentration of ergotamine was not measured, the likeliest explanation was that the serious side effects were related to the altered pharmacokinetics and loss of first-pass metabolism of the drug due to the venous bypass of the liver.