Antihyperglycemic agents from natural and synthetic sources have been found to successfully manage diabetes. This study was to hypothesis that the oral administration of p-coumaric acid regulates blood glucose and antioxidant levels in streptozotocin (STZ) induced diabetic rats. The STZ induced diabetic rats exhibited increased level of blood glucose, lowered the level of insulin, and decreased the activities of enzymatic and non enzymatic antioxidants in blood as compared with normal rats. Oral administration of p-coumaric acid (100 mg/kg b.wt) was given for a period of 30 days. In our study we recognized that the administration of p-coumaric acid could be lowered blood glucose and improve the level of insulin, enzymatic and non enzymatic antioxidants activities in circulation. The histopathological study of pancreas, liver and kidney revealed the protective role of p-coumaric acid. We could not observe any significant changes in all the biochemical and histopathological studied in normal rats treated with pcoumaric acid. The overall results suggest that the p-coumaric acid possesses potential antihyperglycemic and antioxidant activity in STZ-induced diabetic rats.