Beta-sitosterol belongs to the group of phytosterols that is of plant origin and, in terms of chemistry, is similar to cholesterol. It occurs in a number of plants, including peanuts and peanut products, such as peanut oil and peanut butter. Depending on the variety, 100 g of roasted peanuts contain 61-114 mg of phytosterol. This is composed of approx. 80% beta-sitosterol. With its protective effect on the bowel and prostate and its preventive effect against breast cancer, beta-sitosterol is very important for nutritional science. Thus, the consumption of high doses, of some 3-6 g per day, increases uptake of cholesterol from the gastrointestinal tract and lowers cholesterol levels in the blood. In a trade setting, it is found in specially enriched formulations, for instance in cholesterol-lowering margarines and milk products. Furthermore, studies prove the inhibitory effect of beta-sitosterol with respect to the growth of tumours and the spread of metastases, particularly in breast cancer. A higher intake of beta-sitosterol in the diet is therefore, without doubt, very beneficial to maintaining good health.