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 nephrotoxicityin 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 (1,000mg/kg, p.o.), MS (650 mg/kg, p.o.) and MI (350 mg/kg, p.o.) respectively for ten days. On 10thday a single dose of the mercuric chloride (3 mg/kg, s.c.) was also administered to all groupsexcept the group I which received only 1% CMC (10 ml/kg, p.o.). After two days of mercuricchloride administration the blood samples of each animal were collected and analyzed for bloodurea nitrogen and creatinine concentration. Rats fed with Kundur and MI fraction showed asignificant prevention in the rise of serum markers while MS failed to prevent the rise of theseserum makers. These results suggest that Kundur and MI fraction may have potential to reducethe nephrotoxicity in rats.