Basil is a culinary herb in the Lamiaceae (mint) family. It is a tender plant, and is used in cuisines worldwide. In Western cuisine, the generic term "basil" refers to the variety also known as sweet basil or Genovese basil. Basil is native to tropical regions from Central Africa to Southeast Asia. In temperate climates basil is treated as an annual plant, however, basil can be grown as a short-lived perennial or biennial in warmer gardening zones with tropical or Mediterranean climates.

Etymology
The name "basil" comes from the Latin basilius and the Greek basilikon phyton, possibly because the plant was believed to be used in the production of royal perfumes. The Latin name has been confused with basil, as it was supposed to be an antidote to basil poison.

Phytochemistry
Basils have such distinct scents because the volatile aromatic compounds vary among varieties. The essential oil from European basil contains high concentrations of linalool and methylchavicol (estragole), in a ratio of about 3:1. Other components include 1,8-cineole, eugenol, and myrcene. The aroma profile of basil includes 1,8-cineole and methyleugenol. In this species, eugenol is synthesized from coniferyl acetate and NADPH. Some of these are useful as insect repellents.

Varieties
Most basils are varieties of sweet basil. Most basil varieties have green leaves, but some are purple, such as 'Purple Delight.'

Uses

Cuisine:
Basil is most often used fresh in recipes. It is generally added last, as cooking quickly destroys the flavor. The fresh herb can be kept for a short time in the refrigerator or for a longer time in the freezer, after blanching it in boiling water. Basil is one of the main ingredients in pesto, an Italian sauce made with olive oil and basil. Many ethnic cuisines use fresh or dried basil in soups and other foods, such as to thicken soups. Basil is often steeped in cream or milk to create flavor in ice cream or chocolate truffles.

Leaves and flowers:
The most commonly used varieties of Mediterranean basil are "Genovese", "Purple Ruffles", "Mammoth", "Cinnamon", "Lemon", "Globe" and "African Blue".

Seeds:
When soaked in water, the seeds of many varieties of basil become gelatinous and are used in Asian drinks and desserts such as Indian faluda, Iranian sharbat-e-rihan or hột é. In Kashmir, the Ramadan fast, It is often broken with bebre beole, a sorbet made with basil seeds.

Folk medicine:
Basil is used in folk medicine practices, such as those of Ayurveda or traditional Chinese medicine.

Toxicity to parasites and pathogens

Insecticide and insect repellent:
Studies of the essential oil have shown insecticidal and insect repellent properties, including potential toxicity to mosquitoes.

Callosobruchus maculatus, a pest of peas, is repelled by basil essential oil. The essential oil mixed with kaolin is both adulticidal and ovicidal, effective for three months against C. maculatus on peas. The thrips Frankliniella occidentalis and Thrips tabaci are repelled by O. basilicum, making it useful as an insect repellent on other crops.

Nematicide:
The essential oil was found by Malik et al. 1987 and Sangwan et al. 1990 to be nematicide against Tylenchulus semipenetrans, Meloidogyne javanica, Anguina tritici and Heterodera cajani.