Phytosterols, known as plant sterols, are a naturally occurring compounds found in plants. These plant lipid-like compounds are present at low levels in grains, fruits and vegetables. There are tenths of different sterols and related compounds in plant and marine materials with the most common ones beta-sitosterol, stigmasterol, and campesterol.

Since the early 50s, it was shown that phytosterols block the absorption of cholesterol and reduce blood cholesterol levels.
Recently, functional foods containing phytosterols have become available. In the case of most of these products, phytosterols are found esterified with long-chain fatty acids. These phytosterols are derived from soybean oil.