Garlic (Allium sativum L.) is the edible bulb from a plant of the Allium genus, commonly used for flavouring in cooking and for its beneficial effects for human health. Despite the numerous therapeutic effects attributed to garlic, the chemistry behind its health-promoting effects is still poorly understood. This book attempts to address this problem, as well as the effects of garlic on cardiovascular diseases and the side effects that may develop from the consumption of garlic. This book also briefly overviews the occurrence and chemistry of garlic constituents, and reviews the latest evidence in accordance with anticancer properties of garlic and/or garlic constituents, with special emphasise on the mechanism of action behind their chemoprevention effects. Furthermore, the research advances on the chemistry and pharmacology of garlic and the potential and molecular mechanism of garlic mediated attenuation of heavy metal toxicity are discussed. Other chapters in this book explore the relationship between garlic consumption and prostate cancer, among other diseases and the effects of gamma rays on storage leaf of garlic bulbs in terms of phase properties of microsomal membranes and their lipid and fatty acid composition.