Ichnocarpus frutescens, Ficus dalhousie, Crateva magna, Alpinia galangal, and Swertia chiraita are well-known plants available throughout India and they are commonly used for the treatment of various diseases including diabetes mellitus. The antidiabetic activity of the individual plant parts is well known, but the synergistic or combined effects are unclear. Polyherbal formulations enhance the therapeutic action and reduce the concentrations of single herbs, thereby reducing adverse events. The aim of the present study is to formulate a polyherbal tea bag formulation and evaluate its in vivo antidiabetic potential. The polyherbal formulation was formulated using the crude powder of the plants. The herbal formulation depicts hyperglycemic effects in both normal and experimentally induced hyperglycemia rats. The antidiabetic activity of the polyherbal formulation (100 mL/kg b.w.) was screened against streptozotocin-nicotinamide induced diabetes mellitus in rats. The infusion extract was administered for 21 consecutive days, and the effect of the polyherbal formulation on blood glucose levels was studied at regular intervals. At the end of the study, the blood samples were collected from all the animals for biochemical estimation (SGOT and SGPT). Polyherbal tea bag formulation showed significant antidiabetic activity and this effect was comparable with that of Metformin.