Garlic (Allium sativa), is a plant with long, flat grasslike leaves and a papery hood around the flowers. The stalk rises directly from the flower bulb, which is the part of the plant used as food and medicine. The bulb is made up of many smaller bulbs covered with a papery skin known as cloves.
The most active components of fresh garlic are an amino acid called alliin and an enzyme called allinase. When a clove of garlic is chewed, chopped, bruised, or cut, these compounds mix to form allicin, which is responsible for garlic's strong smell. Allicin, in turn, breaks down into other sulfur compounds within a few hours.
Garlic also contains a wide range of trace minerals. These include copper, iron, zinc, magnesium, germanium, and selenium. In addition, garlic contains many sulfur compounds, vitamins A and C, and various amino acids.