Sine the autumn of 1995, Benecol, a proprietary brand of cholesterol-lowering margarine, has been available in ordinary grocery shops in Finland. The active ingredient is a sitostanol ester. Several studies in humans have shown use of the margarine to result in an approximately 10 per cent reduction in total serum cholesterol, and a 13-15 per cent reduction of LDL-cholesterol. However, further studies are required of its phyto-oestrogenic and endocrine effects, and its effects on growing children, particularly regarding subsequent fertility in boys. Although the margarine is classed as a 'functional food' in Finland, the question arises where the line is to be drawn between medicines and food-stuffs.