Lack of toxicity of chenodeoxycholic acid in the squirrel monkey.

The toxicity of chenodeoxycholic acid was studied in squirrel monkeys of both sexes. The drug was orally administered to five groups of 26 animals each at a daily dose of 0, 10, 20, 40, and 80 mg per kg, respectively, for a maximum of 52 weeks. No clinical symptoms that could suggest drug toxicity were observed. All laboratory studies, including liver function tests, were within normal limits. The proportion of lithocholic acid in biliary acids remained unchanged, whereas that of chenodeoxycholic acid was dose-dependently increased. No histopathological changes considered to be attributable to drug administration were observed.