In alloxan diabetes, serum GOT, GPT, and ceruloplasmin were significantly increased compared to normal rats, while the level of serum alkaline phosphatale was decreased. Treatment with insulin led to lowering of serum GOT, GPT, and ceruloplasmin while serum alkaline phosphatase remained low. Then lycanol or daonil were used for treatment, serum GOT, GPT, and ceruloplasmin were changes towards normalization, while ceruloplasmin returned to normal values. Serum-alkaline phosphatase increased after 7 and 14 days from treatment with oral hypolygylcaemic drugs. In dithizonized diabetic animals, the levels of serum GOT, GPT, and alkaline phosphatase were found to be higher than normal, while ceruloplasmin levels were unchanged. After treatment with insulin all serum enzyme activities were normalized.