The aim of the study was to evaluate the antidiabetic activity of polyherbal formulation I and II in streptozotocin (STZ) induced type 2 diabetic mice. Swiss albino female mice were used for the present study. Acute toxicity study was done on screened mice for 14 days. The mice were divided into five groups like normal, diabetic, formulation I and II treated and standard (diabetes treated with metformin). STZ 20 mg/kg body weight (bw) was administered intra-peritoneally to mice for the induction of type 2 diabetes. After the confirmation for diabetes, the mice were subjected to further in-vivo studies. The poly herbal formulations I and II (100 mg/kg bw) were administered orally to diabetic mice for 28 days. The poly herbal formulation I contains Eclipta prostrata (leaves), Syzygium cumini (seeds), Phyllanthus niruri (leaves) and formulation II contains Eclipta prostrate (leaves), Syzygium cumini (seeds), in the ratio of 1:2:1 and 1:2 respectively. Body weight and fasted blood glucose levels were monitored and recorded every week. The fasted mice were examined for the period of 28 days after which they were sacrificed. The blood and tissue samples were collected for analyses of biochemical parameters and for other related tests. Biochemical parameters like blood glucose level, lipid profile test and kidney profile test were done to confirm the efficacy of the formulations. Formulation I and II did not show any toxicity at the level upto 250 mg/kg bw. Based on the toxicity studies, dosage level was fixed to 100 mg/kg bw. Formulation I showed significant antidiabetic effect than formulation II in STZ-induced diabetic mice. This might conclude that the polyherbal formulation I possess most efficient in antidiabetic activity when compared to formulation II and metformin. © protected.