In view of alleged, the methanolic extract of Equisetum arvense was analysed for its antidiabetic activity in streptozotocin-induced diabetic rats. The blood glucose lowering activity of the methanolic extract was determined in streptozotocin-induced (50 mg kg(-1), i.p.; dissolved in normal saline) diabetic rats, after oral administration in doses of 50 and 250 mg kg(-1) daily for 5 weeks. The data was compare statistically using one-way ANOVA tukey test. The results showed methanolic extract of Equisetum arvense produced a significant antidiabetic activity at doses 50 and 50 mg kg(-1)/b.wt. Concurrent histological studies of the pancreas of these animals showed comparable regeneration by methanolic extract which were earlier, necrosed by streptozotocin.