The first one comes from Elson M. Haas M.D.
Now that I have devoted so many pages to nutrients, foods, diets, and special eating plans to support health and to treat a variety of disease states, it is important to emphasize a number of programs in the category of elimination--both the basic process of detoxification and programs that will help us cleanse specific common toxins and habits from our lives.
It is somewhat difficult to separate the concepts and practices of detoxification from those of fasting. Fasting, or the avoidance of solid food, as I use the term here, is one method of detoxification, probably the most effective, yet extreme, form. There are many other ways to detoxify.
Toxicity is of much greater concern in the twentieth century than ever before. There are many new and stronger chemicals, air and water pollution, radiation and nuclear power. We ingest new chemicals, use more drugs of all kinds, eat more sugar and refined foods, and daily abuse ourselves with various stimulants and sedatives. The incidence of many toxicity diseases has increased as well. Cancer and cardiovascular disease are two of the main ones. Arthritis, allergies, obesity, and many skin problems are others. In addition, a wide range of symptoms, such as headaches, fatigue, pains, coughs, gastrointestinal problems, and problems from immune weakness, can all be related to toxicity.
This second one I found on Wikipedia:
Detoxification, or detox for short is the removal of toxic substances from the body. In conventional medicine, detoxification can also be achieved artificially by techniques such as dialysis and (in a very limited number of cases) chelation therapy.
This last one I found at The Light Party:
Detoxification is the process of clearing toxins from the body or neutralizing or transforming them, and clearing excess mucus and congestion. Many of these toxins come from our diet, drug use, and environmental exposure, both acute and chronic. Internally, fats, especially oxidized fats and cholesterol, free radicals, and other irritating molecules act as toxins. Poor digestion, colon sluggishness and dysfunction, reduced liver function, and poor elimination through the kidneys, respiratory tract, and skin all add to increased toxicity.
Detoxification involves dietary and lifestyle changes which reduce intake of toxins and improve elimination. Avoidance of chemicals, from food or other sources, refined food, sugar, caffeine, alcohol, tobacco, and many drugs helps minimize the toxin load. Those lifestyle changes are a direct result of choices you make in your life.