\Many studies have shown that niacin and Cr exert combined effects. Significant beneficial effects in serum lipid levels following Cr supplementation have been reported. Niacin decreases total plasma levels of cholesterol, triglycerides, and low-density lipoprotein cholesterol and increases high-density lipoprotein cholesterol. In this study, 12-mo-old female Swiss albino rats were used. They were randomly divided into four groups. The animals of group I (control) were fed with pellet chow. Group II was fed with pellet chow and treated with 250 mug/kg CrCl3-6H(2)O and 100 mg/kg niacin for 45 d, by the gavage technique. The rats of group III were fed with lipogenic diet consisting of 2% cholesterol, 0.5% cholic acid, and 20% sunflower oil added to the pellet chow and given 3% alcoholic water for 60 d. Group IV was fed with the same lipogenic diet, and 15 d after, the experimental animals were made hyperlipemic; they were treated with 250 mug/kg CrCl3-6H(2)O and 100 mg/kg niacin by gavage technique for 45 d. On d 60, liver and blood samples were taken from the animals. The sections were examined under light and electron microscopes. Serum total lipid and cholesterol levels were determined by spectrophotometric methods. The aim of the present study was to examine whether combined treatment with Cr and niacin have beneficial effects on the liver of animals fed with lipogenic diet. In this study, beneficial effects of combined treatment with niacin and Cr(III) were evaluated. We conclude that a combination of Cr and niacin decrease total cholesterol and total lipid levels in serum significantly. In addition, it can be said that niacin and Cr can regenerate some of the hepatocytes. This study reveals that combined treatment is a better specific drug in hyperlipemia.