The anti-hyperglycemic and antioxidant potential of Nisha Kathakathadhi Churnam (NKC), an ayurvedic formulation, was estimated in alloxan-induced, hyperglycemic rats. Various enzymatic antioxidants, such as, superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione and lipid peroxidation were estimated in the heart and pancreas of hyperglycemic rats. The effect of NKC on blood glucose levels was estimated on days 0, 10, 20 and 30 of a 30-day study. A marked decrease in the blood glucose levels ( P < 0.001) was observed in hyperglycemic rats and the decreased activities of the key antioxidant enzymes increased to near normal (P< 0.01) levels and the increased lipid peroxidation decreased in diabetic rats upon NKC treatment. These results suggest that NKC has promising antidiabetic and antioxidant activities in alloxan-induced diabetes.