This study was designed to evaluate the effects of some antidiabetic agents in albino rats by the selection of two antidiabetic agents, one of which is chemical (metformin) and the other is a natural plant (Costus), and to investigate their possible beneficial effects on diabetes. A total of 36 normal male albino rats were randomly assigned into six equal groups. Three of them were normal rats. The first normal group served as the control group. The second normal group received costus rhizome extract at a dose of 250 mg/kg/b.w once a day for 30 days. The third normal group received metformin cure at a dose of 500 mg/kg/b.w once a day for 30 days. The other three groups were diabetic rats that injected STZ (45 mg/ kg b.w /i.p.). The first diabetic group served as control group. The second diabetic group received costus rhizome extract at a dose of 250 mg/kg/b.w by oral gavage once a day for 30 days, the third diabetic group received metformin cure at a dose of 500 mg/kg/b.w by oral gavage once a day for 30 days. Our results showed that metformin and hexane extract of costus sp. treated groups revealed enhancement and improvement of disturbance of liver functions, kidney functions, immunological parameters, antioxidant parameters and histopathology of the pancreas.