Diabetes mellitus is described as a metabolic disorder of multiple etiology, characterized by chronic hyperglycemia with disturbances of carbohydrate, lipid and protein metabolism, resulting from defects in insulin secretion, insulin action, or both. Looking into the pharmacological properties of different plant varieties like Allium cepa, Trigonella foenum-graecum, Tinospora cordifolia, Gymnema sylvestre, Syzygium cumini and Momordica charantia, the study was carried out to evaluate the effect of polyherbal extract mixture (PHEM) on blood glucose level, lipid profile and other pathophysiological alterations in streptozotocin induced diabetic rats. Thirty Sprague-Dawley rats were randomly divided based on body weight in five groups (C1, C2, C3, T1 and T2). Rats of four groups (C2, C3, T1 and T2) were injected with streptozotocin to induce diabetes. Rats of group C1, C2, and C3 were kept as normal, diabetic and standard control, respectively. Rats of group C3 were administrated with glibenclamide (5 mg/kg, PO for 28 days). Rats of group T1 and T2 were treated with PHEM at 100 and 200 mg/kg, respectively orally for 28 days. Administration of PHEM significantly reduced the blood glucose level in T1 and T2 experimental groups after 28 days of treatment. In lipid profile, mean values of total cholesterol, triglyceride, HDL-cholesterol and LDL-cholesterol in rats treated with PHEM were found comparable to those of control rats. Altered biochemical enzymes like AST, ALT, ALP and bilirubin were normalized by administration of PHEM in diabetic rats. Antioxidant enzymes which got altered in diabetic rats were also normalized in rats under the treatment of PHEM. In conclusion, administration of polyherbal extract mixture at the dose rate of 200 mg/kg, PO for 28 days have shown ameliorating effect against STZ induced alterations in glucose level, lipid profile, oxidative status and other pathological changes in rats.