Complications of diabetes includes decisive role of oxidative stress. This study was aimed to identify the role of an ayurvedic preparation, Pramehari ark which is made up of most potent antidiabetic herb Pterocarpus marsupium and connoisseur antioxidant Cow urine against streptozotocin-nicotinamide (STZ-NA) induced diabetic rats.   Female Wistar Albino rats were divided in six groups randomly. STZ (45mg/kg, i.p.) was injected to induce diabetes. 15 min prior to STZ, Nicotinamide (90 mg/kg, i.p.) was given. Treatment was given for 4 months and after which various biochemical, urinary, oxidant, inflammatory, histological etc parameters were estimated. Diabetic rats showed significant increase in plasma glucose level were selected for further study. The levels of the antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), Glutathione, Lipid peroxidation glucose (MDA) were estimated. Estimation of Fasting blood (FBG), Total cholesterol (TC), Triglycerides (TG), Low density lipoproteins (LDL) were found higher in diabetic control group. Other enzyme levels like SGPT, SGOT, LDH, CRP, CK-MB, Creatinine, BUN was also measured. Oral treatment with Pramehari ark for 120 days demonstrated significant protective effects on all the biochemical parameters studied. Results of the histopathological studies and hypertrophic parameters also support the biochemical findings.  These results revealed that Pramehari ark has potential protective effect against diabetes and its complications possibly via inhibition of oxidative stress and inflammatory markers.