In the present study, the hypoglycemic activity of Withania somnifera
Dunal, Allium sativum
Linn., Gymnema sylvestre
(Retz.) Schult, Ferula foetida
(Bunge.) Reg. and Murraya koenigii
(L.) Spreng. extracts have been studied in an experimental model of type 1 diabetes. Type 1 diabetes was induced in albino rats by a single intraperitoneal injection of streptozotocin (60 mg/kg). Rats with fasting blood glucose (FBG) more than 250 mg/dl, 72 h after STZ administration, were treated with extracts of above mentioned medicinal plants. The fasting blood glucose was determined every week for 3 weeks by the glucose oxidase method. STZ-administration led to a highly significant elevation in FBG levels. The percent decrease in FBG levels from STZ-induced hyperglycemia was 43.3 ± 27.8, 48.2 ± 22.4 and 48.2 ± 7.9, after 3 weeks of treatment with standardised extracts of Withania somnifera (1.5% withanolides), Allium sativum (0.6% allicin) and Gymnema sylvestre (75% gymnemic acid), respectively. The fall in blood glucose with the herbal extracts was less when compared to insulin. In the vehicle treated group, there was 8.8 ± 9.3 percent increase in blood glucose values at the third week of treatment and in insulin treated group, percent decrease in blood glucose from the values obtained at 72 h after STZ-administration was 63.5 ± 4.9. Ferula foetida (60% ferulic acid) and Murraya koenigii extracts did not show any hypoglycemic effect in animal model of type 1 diabetes.