The polysaccharide from blackgram has been reported previously to show a cholesterol-, phospholipid- and triglyceride-lowering effect on serum, liver and aorta in rats fed a high fat-high cholesterol diet. The effect of feeding the polysaccharide as the only source of carbohydrate to rats fed an otherwise normal diet, has now been studied and compared with feeding glucose and sucrose. The polysaccharide produces lower levels of total cholesterol and phospholipids in serum, liver and aorta than does glucose. The triglyceride levels are more or less comparable in the serum and aorta, in the two groups, but lower in the liver in the polysaccharide group. Sucrose, on the other hand, produces higher levels of these lipids in these tissues. Lipoprotein lipase activity is higher in the aorta, liver and heart in the rats fed glucose and polysaccharide, but is considerably decreased in the sucrose group. The individual glycosaminoglycans of the aorta are more or less comparable in both the glucose and polysaccharide group. Hyaluronic acid, chondroitin sulphate, A, B, and heparin being slightly raised in the polysaccharide group, while heparan sulphate and chondroitin sulphate C are lower. On the other hand, animals fed sucrose show considerably decreased levels of all these fractions. The levels of soluble protein in the liver and aorta are more or less similar in the polysaccharide and glucose groups, but are decreased in the sucrose group. The hepatic glycogen, however, is lowest in the polysaccharide group and highest in the sucrose group. The fasting blood glucose levels are within the normal range in the animals of the 3 groups, but the level I h after an oral glucose load is higher in the sucrose group. The excretion of faecal sterols and bile salts is maximum in the polysaccharide group and minimum in the sucrose group.