Garlic (Allium sativum), a herb used widely as a flavoring in cooking, has also been used as a medicine throughout ancient and modern history to prevent and treat a wide range of conditions and diseases. Garlic belongs to the onion genus Allium, and is closely related to the onion, rakkyo, chive, leek, and shallot.arlic is a popular ingredient in cooking and may also have some health benefits. The original Olympic athletes in Ancient Greece were given garlic-possibly the earliest example of performance enhancing agents used in sports.