Propafenone, three times 150 mg/d over 33 days and two years later at the same dosage over six days, was administered to an 84-year-old man with ventricular extrasystoles (Lown IVa). Both times intrahepatic biliary stasis occurred, presumably a sign of a drug-allergic hepatitis. All other possible causes in the differential diagnosis were excluded. The lymphocyte transformation test demonstrated in vitro propafenone-sensitive patient-lymphocytes.