The effect of Kundur (oleo-gum resin of Boswellia serrata) and its fractions viz: methanol soluble (MS) and methanol insoluble (MI) were investigated on mercuric chloride induced nephrotoxicity in rats. The animals of group I and II were administered with 1% carboxymethyl cellulose (CMC) (1,000 mg/kg, p.o.) and the animals of groups III, IV and V were administered with Kundur (1,000 mg/kg, p.o.), MS (650 mg/kg, p.o.) and MI (350 mg/kg, p.o.) respectively for ten days. On 10th day a single dose of the mercuric chloride (3 mg/kg, 5.c.) was also administered to all groups except the group I which received only 1% CMC (10 ml/kg, p.o.). After two days of mercuric chloride administration the blood samples of each animal were collected and analyzed for blood urea nitrogen and creatinine concentration. Rats fed with Kundur and MI fraction showed a significant prevention in the rise of serum markers while MS failed to prevent the rise of these serum makers. These results suggest that Kundur and MI fraction may have potential to reduce the nephrotoxicity in rats.