Abstract: Objective To investigate the repeated dose toxicity of clarithromycin for injection in dogs. Methods The normal dogs were administered with clarithromycin for injection by intravenous injection for four weeks. The body weight,blood biochemistry, hematology, viscera relative weight and histopathology were measured for the overall toxicity assessment. Results The normal dogs administered with clarithromycin for injection( 80mg·kg^-1) showed abnormal escalation of the levels of aspartic transaminase(AST), alanine aminotransferase(ALT), urea nitrogen(BUN). Histopathological examination indicated that the liver cells were cord -like arranged and perisinusoidal space was broadened,some liver cells degenerated, necrosed or appeared karyopyknosis. Renal capillary dilatation and congestion, epithelial cell degeneration, necrosis or pyknosis of partial renal tubular were also found by histopathological examination. Conclusion Repeated administration of clarithromycin at high dose could lead to abnormal biochemical index and pathological lesions of liver and kidney in dogs.

Key words: clarithromycin for injection, dog, repeated dose toxicity