Abstract: Objective To investigate the long-term toxicity of oral treatment of total saponins from Medicago sativa L. (TSM) on Beagle dogs. Methods Beagle dogs were divided into 4 groups at random (n=8), namely normal control, TSM high, medium and low dose groups (3.2, 1.6 and 0.8 g?kg-1, respectively). TSM was orally administered for 180 days. The body weight, behavior and food intake of animals were observed during the administration. The hematology and blood biochemistry analysis were carried out, and organ histopathological changes were observed under the microscope at the end of the administration and 30 days after the administration, respectively. Results The outer appearance, behavior and body weights in dogs of TSM groups showed no significant differences compared to those of normal control group. In hematology and blood biochemistry analysis, white blood cell count was increased while aminopherase activity was decreased in the blood of TSM high dose group. The levels of total protein and creatinine were significantly increased in TSM medium and low dose group, respectively. This may attribute to the stress response or individual difference of some Beagle dogs. In addition, no changes related to TSM among other indices were observed. TSM showed no apparent influence in organs of dogs in histopathological observation. In addition, no delayed toxicity reaction was showed 30 days after the administration. Conclusion TSM (0.8 to 3.2 g?kg-1) shows no obvious toxicity in Beagle dogs for long-term administration.

Key words: total saponins from Medicago sativa L., Beagle dog, long-term toxicity