Roots of Illupai (Madhuca longifolia) are mentioned for Madhumegam in Gunapadam -Mooligai (Siddha Materia Medica). The disease Madhumegam found in siddha text is correlated with Diabetes mellitus type-II. Madhuca longifolia known as Illupai in Tamil has been widely used for the treatment of diabetes. Hence, the present study aimed to demonstrate the antidiabetic effects of Illupai ver chooranam in normal and streptozotocin (STZ) induced diabetic rats. The qualitative phytochemical analysis of the chooranam showed the presence of flavonoids, glycosides, tannins, triterpenoids, polyphenols, carbohydrates, steroids, saponin and proteins. Acute toxicity studies revealed the nontoxic nature of the illupai ver chooranam up to a dose level 2000 mg/kg body weight until the end of the study period. The illupai ver chooranam (500 and 1000 mg/kg) significantly reduced (P**< 0.01) glucose levels in diabetic rats. The other biochemical parameters like cholesterol, lipid, urea, protein, liver glycogen, serum glutamate pyruvate transaminase (SGPT) and serum glutamate oxaloacetate transaminase (SGOT), were found to be reduced by the illupai ver chooranam. The histopathological results of treated groups showed the regenerative/protective effect on ?-cells of pancreas in diabetic rats. In the oral glucose tolerance test, the illupai ver chooranam increased the glucose tolerance. The current study revealed the antidiabetic potential of illupai ver chooranam effective in hyperglycemia and that it can effectively protect against other metabolic aberrations caused by diabetes in rats, which seems to validate its therapeutic traditional use.