Allium sativum, commonly known as garlic, is a species in the onion family Alliaceae. Its close relatives include the onion, shallot, leek, and chive. Garlic has been used throughout recorded history for both culinary and medicinal purposes. It has a characteristic pungent, spicy flavor that mellows and sweetens considerably with cooking. A bulb of garlic, the most commonly used part of the plant, is divided into numerous fleshy sections called cloves. Single clove garlic (also called Pearl garlic or Solo garlic) also exists—it originates in the Yunnan province of China. The cloves are used as seed, for consumption (raw or cooked), and for medicinal purposes. The leaves, stems (scape), and flowers (bulbils) on the head (spathe) are also edible and are most often consumed while immature and still tender. The papery, protective layers of "skin" over various parts of the plant and the roots attached to the bulb are the only parts not considered palatable.
The ancestry of cultivated garlic, according to Zohary and Hopf, is not definitely established: "A difficulty in the identification of its wild progenitor is the sterility of the cultivars."
Allium sativum grows in the wild in areas where it has become naturalised; it probably descended from the species Allium longicuspis, which grows wild in southwestern Asia. The "wild garlic", "crow garlic", and "field garlic" of Britain are the species Allium ursinum, Allium vineale, and Allium oleraceum, respectively. In North America, Allium vineale (known as "wild garlic" or "crow garlic") and Allium canadense, known as "meadow garlic" or "wild garlic" and "wild onion", are common weeds in fields. One of the best-known "garlics", the so-called elephant garlic, is actually a wild leek (Allium ampeloprasum). It is called "Sudu Lunu" in Sinhalese, Lehsun in Urdu and Hindi, Velli ullipaaya in Telugu and Vellai poondu in Tamil.
Garlic is widely used around the world for its pungent flavor as a seasoning or condiment. It is a fundamental component in many or most dishes of various regions, including eastern Asia, south Asia, Southeast Asia, the Middle East, northern Africa, southern Europe, and parts of South and Central America. The flavour varies in intensity and aroma with the different cooking methods. It is often paired with onion, tomato, or ginger. The parchment-like skin is much like the skin of an onion and is typically removed before using in raw or cooked form. An alternative is to cut the top off the bulb, coat the cloves by dribbling olive oil (or other oil-based seasoning) over them, and roast them in an oven. The garlic softens and can be extracted from the cloves by squeezing the (root) end of the bulb, or individually by squeezing one end of the clove. In Japan and Korea, heads of garlic are fermented at high temperature; the resulting product, called black garlic, is sweet and syrupy, and is now being sold in the United States also.
Garlic may be applied to breads to create a variety of classic cuisines such as garlic bread, garlic toast, bruschetta, crostini and canapé.
Oils are often flavored with garlic cloves. These infused oils are used to season all categories of vegetables, meats, breads and pasta.
In some cuisine, the young bulbs are pickled for 3–6 weeks in a mixture of sugar, salt, and spices. In eastern Europe, the shoots are pickled and eaten as an appetizer.
Immature scapes are tender and edible. They are also known as "garlic spears", "stems", or "tops". Scapes generally have a milder taste than cloves. They are often used in stir frying or prepared like asparagus. Garlic leaves are a popular vegetable in many parts of Asia. The leaves are cut, cleaned, and then stir-fried with eggs, meat, or vegetables.
Mixing garlic with eggs and olive oil produces aioli. Garlic, oil, and a chunky base produce skordalia. Blending garlic, almond, oil, and soaked bread produces ajoblanco.
Garlic powder has a different taste than fresh garlic. If used as a substitute for fresh garlic, 1/4 teaspoon of garlic powder is equivalent to one clove of garlic.