Human ehrlichiosis: a rickettsial disease associated with severe cholestasis and multisystemic disease. We report an unusual case of a typically canine rickettsial disease, ehrlichiosis, in a 56-year-old man. Although only occasionally affecting humans with a mild illness, exposure to a tick bite in our patient led to severe multisystemic disease with intense cholestasis. Coma, acute renal failure and respiratory failure requiring mechanical ventilation ensued. Imaging procedures showed no biliary obstruction. A liver biopsy demonstrated bile stasis and sinusoidal lymphoid infiltrates. The diagnosis was confirmed serologically. Only partial improvement occurred with tetracycline therapy, but total resolution of all abnormalities eventually followed therapy with chloramphenicol. 