Saw palmetto extract is an extract of the fruit of the saw palmetto. There are large populations in saw palmetto prairie habitat. Examples are tannins from foods, such as tea and saw palmetto, phytic acid, and roughage. Beta-sitosterol, a chemical present in saw palmetto extract, is chemically similar to cholesterol. The combination of saw palmetto extract with estrogen products should be used with caution. It is a constituent of saw palmetto ("Serenoa"). Alternative medicine, such as saw palmetto, does not appear to help. Saw palmetto extract should not be used during pregnancy. The shrub layer is dominated by saw palmetto ("Serenoa repen"s). Saw palmetto is used in several forms of traditional herbal medicine. Xeric hammocks are characterized by sand live oak ("Quercus geminata") and saw palmetto ("Serenoa repens").