Garlic is one of the components, which have effects on reducing the risk of cancer. Including garlic in the diet helps for the betterment of the health. Medicinal effects of the garlic were known since 5,000 years. Recently, studies were carried out to known its effect on the cancer cell lines. Many studies have shown its effects not only on carcinomas, but also on the cardiovascular system and immune system. Functions of the each component of the garlic were studied to know exactly, which component has got beneficial effect. So this review has been carried out to know about the component, functions of each component, mode of action, and beneficial effects of the garlic.