Review of published studies suggests that high dietary content of soluble fibre can reduce serum cholesterol by up to 17%. The reduction may be proportional to the degree of hypercholesterolemia before the change in diet. The mechanism is not fully elucidated. It may be analogous to the effect of anion-binding-resins on the metabolism of bile acids and cholesterol but it may also be due to partial substitution of soluble fibre for dietary saturated fat which causes elevation in serum cholesterol.