Plant sterol/stanol margarines are recommended as a lipid-lowering dietary supplement in the treatment of hypercholesterolaemia. Parameters predicting the individual cholesterol-lowering effect have not been elucidated so far, therefore German researchers investigated the responsiveness to sitostanol-supplemented margarine in a specially selected population. From a total number of 137 male subjects with hypercholesterolaemia, eight subjects with the lowest and eight subjects with the highest ratios of lathosterol to campesterol in serum were included in the study. They received 1 g sitostanol-supplemented margarine twice daily for 4 weeks. Serum lipoproteins, the cholesterol precursor lathosterol, and the plant sterols campesterol and sitosterol were measured. Subjects with a low ratio of lathosterol to campesterol had a significant decrease in serum total cholesterol and LDL-C. In subjects with a high ratio there was no significant change in total cholesterol and LDL-C.