Present investigation was undertaken to evaluate antihyperglycemic, antihyperlipidemic and antioxidant activities of Dihar, a polyherbal formulation containing drugs from eight different herbs viz., Syzygium cumini, Momordica charantia, Emblica officinalis, Gymnema sylvestre, Enicostemma littorale, Azadirachta indica, Tinospora cordifolia and Curcuma longa in streptozotocin (STZ, 45 mg/kg iv single dose) induced type 1 diabetic rats. STZ produced a significant increase in serum glucose, cholesterol, triglyceride, very low density lipoprotein, low density lipoprotein, creatinine, and urea levels in diabetic rat. Treatment with Dihar (100 mg/kg) for 6 weeks produced decrease in STZ induced serum glucose and lipids levels and increased insulin levels as compared to control. Dihar produced significant decrease in serum creatinine and urea levels in diabetic rats. There was a significant decrease in reduced glutathione, superoxide dismutase, catalase levels and increase in thiobarbituiric acid reactive species levels in the liver of STZ-induced diabetic rats. Administration of Dihar to diabetic rats significantly reduced the levels of lipid paroxidation and increased the activities of antioxidant enzymes. The results suggest Dihar to be beneficial for the treatment of type 1 diabetes.