Liver involvement was retrospectively evaluated in 137 patients with murine typhus. Fifteen (10.9%) were jaundiced. One patient had been subjected to cholecystectomy after misdiagnosis of acute cholecystitis. Serum aminotransferase levels were abnormal in 48/52 measurements, and there were elevations of > 5-fold in 14 patients. Liver biopsies and/or necropsies from four jaundiced patients showed portal tract and sinusoidal infiltrates, cloudy swelling/and necrosis of the hepatocytes and occasional pseudogranuloma formation. There were striking mitoses even in the early stage, suggesting rapid hepatocellular regeneration. Haemolytic diseases (G6PD deficiency or haemoglobinopathies), alcoholism, and a second infection probably also contributed to the pathogenesis of jaundice in murine typhus. This rickettsiosis should be included among differential diagnoses of acute hepatitis in patients exposed to areas endemic for Rickettsia typhi.