Beta-carotene, derived from the Latin name for carrot, belongs to a family of natural chemicals known as carotenes or carotenoids. Widely found in plants, carotenes give yellow and orange fruits and vegetables their rich colors. Beta-carotene is also used as a coloring agent for foods such as margarine.

Beta-carotene is converted to vitamin A (retinol) by the body. While excessive amounts of vitamin A in supplement form can be toxic, the body will only convert as much vitamin A from beta-carotene as it needs. This feature makes beta-carotene a safe source of vitamin A.

Like all other carotenoids, beta-carotene is an antioxidant. Consuming foods rich in beta-carotene appears to protect the body from damaging molecules called free radicals. Free radicals cause damage to cells through a process known as oxidation, and over time, such damage can lead to a variety of chronic illnesses. Some studies suggest that dietary intake of beta-carotene may reduce the risk of two types of chronic illness-heart disease and cancer. Supplementation, however, is more controversial; see discussion in the section that follows.