The objective of the study was to evaluate the efficacy of garcinol as an antidiabetic candidate in streptozotocin-induced diabetic Wistar rats. Diabetic rats showed a significant increase in the biochemical parameters such as fasting blood glucose, glycated haemoglobin, urea, alanine aminotransferase and aspartate aminotransferase, malondialdehyde, total cholesterol, triglycerides, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, atherogenic index and a significant decrease in plasma insulin, HOMA--cell functioning index, glycogen, high-density lipoprotein cholesterol, body weight and antioxidant enzyme activities, viz. superoxide dismutase, catalase and reduced glutathione. Oral administration of garcinol (10 and 20mg/kg body weight/day) for 30 days improved the above-mentioned alterations. The effect produced by the drug was compared with that of glibenclamide, a standard hypoglycaemic drug. These findings reveal that garcinol can be a promising antidiabetic candidate in the future.