There is documented evidence of the use of Terminalia chebula for various ailments in the Ayurvedic literature. The extract has been shown to possess glucose lowering activity and to improve insulin sensitivity in animal models of type 2 diabetes mellitus. The present study was carried out to study the dose response relationship of this extract in a rat model of metabolic syndrome. Six groups of rats were fed a high fructose diet (HFD) for a period of 20 days to induce metabolic syndrome. Three doses of fruit extract of T. chebula 50, 100 and 200 mg/kg were administered orally and pioglitazone 2.7 mg/kg was used as a positive control. Blood samples were collected at days 0, 20 and 40 from the tail vein. Systolic blood pressure (SBP) was measured using the tail cuff method and an oral glucose tolerance test (OGTT) was done on the day of blood collection. Administration of HFD for 20 days significantly increased fasting blood glucose (FBG), SBP and the area under the curve of OGTT. On day 40 the FBG in the 50, 100 and 200 mg/kg group was 97.33 +/- 5.82 (NS), 86.83 +/- 5.08 (p = 0.038) and 85.67 +/- 6.74 (p = 0.15), respectively. These results show that the fruit extract of T. chebula exerts a significant and dose-dependent glucose lowering effect in the rat model of metabolic syndrome.