You would be sick all the time if your body did not have ways to detoxify all the bad things that you breathe, drink, eat, and get on your skin. In fact, you could not even live. The world is full of bad chemicals, even without man-made pollution.
But toxins would still be a problem even if we lived in a clean environment. Our own body makes toxic chemicals. For example, did you know that one product the body makes as a by-product of its normal chemical reactions is ethyl alcohol (the kind found in alcoholic drinks)? And the body changes alcohol into an even more toxic compound, acetaldehyde!
Have you heard all the advertisements for Vitamin E and C as substances needed to combat free radicals? Free radicals are normal chemical breakdown products and they are very toxic. Sometimes, these radicals cause cancer and contribute to aging.