Abstract: In order to provide a theoretical basis for rational use drugs in clinic, the regular pattern of different doses of Tilmicosin on blood pressure and heart beat in Saibei rabbits were studied. 24 healthy Saibei rabbits were arranged into 6 groups randomly, the doses of Tilmicosin of the groups were control group（0 mg/kg），Ⅰgroup（20 mg/kg），Ⅱgroup（40 mg/kg），Ⅲ group (60 mg/kg)，Ⅳ group (80 mg/kg)，Ⅴgroup (100 mg/kg) respectively. The blood pressure and heart beat were measured after 7 d feeding with different doses of Tilmicosin. The systolic pressure was decreased by the increased of Tilmicosin,the diastolic pressure was increased gradually as well as the heart rate.The change of clinical symptoms of V gronp was the most significant. The results showed that the suitable dose of Tilmicosin was 20 mg/kg and the safety dose of Tilmicosin for Saibei Rabbit was 100 mg/kg.

Key words: Tilmicosin; blood pressure; heart beat; Saibei rabbit