Xenobiotic is a term used to describe chemical substances that are foreign to animal life and thus includes such examples as plant constituents, drugs, pesticides, cosmetics, flavorings, fragrances, food additives, industrial chemicals and environmental pollutants. It has been estimated that humans are exposed to 1-3 million xenobiotics in their lifetimes. Most of these chemicals that gain access to the body via the diet, air, drinking water, drug administration, and lifestyle choices, undergo a broad range of processes of detoxication that in general render them less toxic, more polar, and readily excretable.