All citrus fruit are excellent sources of Vitamin C, which helps to maintain the body's defences. The flavonoid narigenin is found in grapefruit. It is thought to reduce the risk of some cancers. Grapefruit can improve blood circulation and lower blood cholesterol levels.

Grapefruit is best eaten peeled and raw. This is more beneficial than grapefruit juice. It is important also to eat the skin around the segments. Grapefruit is best eaten when fresh and chilled as this maximizes its vitamin C content.

The grapefruit was first described in the 1750s as the "forbidden fruit" of Barbados. It was introduced to Florida in the 1820s. Most grapefruit in the United States is still grown in Florida. Grapefruit juice has been used in folk medicine for the treatment of diabetes as well as to strengthen the immune system. Grapefruit is also added to cosmetics and hair care products as a fragrance.