The effect of octadecylamide of alginic acid on blood serum and hepatic cholesterol, and the faecal output of fat and sterols was examined in female rats fed diets containing cholesterol and palm fat at 10 and 50 g/kg, respectively for 10 weeks. Amidated alginate, supplied at 10 and 20 g/kg, significantly decreased serum cholesterol from 5.25 to 2.99 and 2.39 μmol/ml, respectively, and decreased hepatic cholesterol from 30.7 to 12.3 and 9.4 μmol/g, respectively. Amidated alginate increased the faecal output of fat and at higher dosing significantly decreased faecal output of bile acids. Faecal output of bile acids and hepatic cholesterol significantly correlated (r = 0.791; P < 0.001). The results of the present experiment showed that hypocholesterolemic effect of amidated alginate persisted within 10 weeks of feeding.