A benzomorphan derivative, pentazocine has both opioid agonistic actions and weak narcotic antagonistic activity. In this paper, authors attempted to study the dose response of pentazocine on the blood sugar level, serum transaminase and alkaline phosphatase activity in rabbits. Eighteen rabbits were devided into 3 groups, and each group were injected with pentazocine 5mg, 15mg, and 30mg/kg respectively. And metabolic effects were investigated measuring the change of blood sugar contents, serum transaminase (S-GOT, S-GPT) activities and alkaline phosphatase activities in rabbits. The results were obtained as follows; 1. Pentazocine significantly increased the blood sugar content in rabbits. 2. Pentazocine significantly increased the serum GOT activity but in the serum GPT activity, it significantly increased in large dose. 3. Pentazocine significantly increased serum alkaline phosphatase activity.