Garlic is one of the oldest medicinal foods used by humans. It is a spice, an herb, and a medicine. Garlic is anti-bacterial, anti-fungal, and anti-viral. Hence, it has been used to stimulate the immune system. In Asian nutrition, garlic is used as a dispersing and warming herb used to treat stagnant conditions both in the body and applied externally. The sulfur compounds in garlic and onions have been found to have protective effects against cancer. Quercetin in onions may block several initiators of cancer cell growth. One or two cloves of garlic or ½ to 1 cup of onions daily offer immune support.