Garlic is a traditional remedy for chronic bronchitis, respiratory catarrh, recurrent colds, and flu. Garlic has been shown to have antibacterial, antiviral, antifungal, antiprotozoal and anti-parasitic properties. Garlic contains sulphur compounds which are concentrated in the bulb. These sulphur compounds include Alliin, a sulphur-containing amino acid. Alliin is responsible for many of the beneficial actions of garlic. Alliin is converted by enzymes naturally occurring in garlic to the active compound Allicin, when garlic is cut, crushed or chewed. Allicin is responsible for the characteristic smell of garlic, and the biological activity of garlic lies in its ability to produce allicin. Allicin is the source of the unique smell of garlic, and it will lose its effect at high temperature, so the cooked garlic may not provide enough allicin to achieve health benefits.