Nonalcoholic steatohepatitis is a poorly understood disease that mimics alcoholic liver disease histologically. Its natural history is not well defined, although gradual progression to cirrhosis has been described. Most patients with this condition have been obese, with or without associated diabetes or hyperlipidemia. No known effective treatment exists for nonalcoholic steatohepatitis, although weight loss may have a beneficial effect. We report two cases of nonalcoholic steatohepatitis. One patient with well-established nonalcoholic steatohepatitis had cirrhosis with a complete loss of fat on subsequent liver biopsy despite a gain in weight, simulating cryptogenic cirrhosis. In another patient, the condition improved after use of ursodeoxycholic acid; this agent may be a potential therapeutic agent for the treatment of nonalcoholic steatohepatitis. We believe these two cases represent the spectrum of this condition: on the one end is a progressive liver disease that in some instances may be a cause of cryptogenic cirrhosis; at the other end, a potentially treatable liver condition.