AbstractThis study evaluated the possible effects of flaxseed oil on renal damage associated with hyperlipidaemic rats. Wistar albino male rats were divided into three groups. Group I was fed with a pellet chow. Group II was fed with a high cholesterol diet (HCD) consisting of 5% cholesterol and 0.35% cholic acid added to the pellet chow. Group III was fed with the same HCD, but were orally treated with a dose of 15 mg/kg body wt/day flaxseed oil. Flaxseed oil treatment started 1 week before and continued throughout the 22 weeks of the HCD. At the end of the experiment, renal tissue and blood samples were collected. The biochemical and histopathological findings confirmed renal damage in hypercholesterolaemia conditions. Flaxseed oil reduced the hypercholesterolaemia‐induced increase in the serum levels of total cholesterol, LDL and urea. Oil red O stain revealed that lowered serum lipid was accompanied by a decreased deposition of neutral lipid. Flaxseed oil effectively reversed these abnormalities, verifying the protective effects of flaxseed oil in ameliorating renal injuries associated with hypercholesterolaemia. Copyright © 2010 John Wiley & Sons, Ltd.