The colon has three main parts: the ascending, transverse and descending colons. Since much of the digestion process has already taken place, what enters the colon is mostly waste material in liquid form. As the colon contracts, this substance is pushed along its length. Most of the water and mineral salts in the liquid are reabsorbed back into the body. What remains is a semi-solid waste, 60-70 percent water and 10-30 percent bacteria, plus indigestible cellulose material, dead cells and other waste materials.

The process of elimination takes anywhere from 12-24 hours or longer. Generally, the shorter the time, the better. Unfortunately, modern diets and health habits sometimes result in greatly increased transit times. As transit time increases, the stool becomes increasingly hardened and difficult to pass due to dehydration. Moreover, as the body reabsorbs the fluid content of the faeces, it also absorbs many soluble toxins.

People whose diets are high in refined foods (including sugar and white flour) and low in fibre content (such as meat, eggs and dairy products) are especially susceptible to intestinal problems. In fact, colon and rectal disorders are much more common in Europe than Africa, where the average diet contains seven times as much fibre.

The colon works best when it is moderately full. Dietary fibre fills this need. Although it contains no nutrients, fibre helps promote good health by providing the necessary bulk to encourage timely movement of fecal material through the colon. As this happens, certain toxic materials are removed along with many times the fibre's weight in water. This is important because it helps maintain bowel regularity and shortens the time toxic materials remain in the body.

There are two basic types of fibre: soluble and insoluble. Soluble fibre includes pectin, gums and some hemicellulose. Fruits, vegetables, seeds, brown rice, barley and oats are sources for soluble fibre. Soluble fibre works mainly by helping to produce a softer stool. It also chemically prevents or reduces the absorption of certain substances into the bloodstream. Insoluble fibre includes cellulose, some hemicellulose and lignin. Whole grains and the outside of seeds, fruits, legumes and other foods are the main sources for insoluble fibre, which works like a sponge, absorbing many times its weight in water and swelling up inside the intestines. The result is more efficient elimination.

When extra fibre is added to the diet, it is important that extra fluids also be added. If not, the beneficial effects can be diminished as the added fibre actually slows down or even blocks proper intestinal elimination. Spreading out fibre intake is also suggested to help ease any unpleasant side effects that may occur at the start of a new, fibre-rich dietary regimen.

Exercise also plays a role in the health of the intestinal system. Without sufficient exercise, bowel action may be slowed down and the normal circulation within the digestive system reduced.

In addition to eating sufficient amounts of fibre.It is important to maintain a good supply of beneficial bacteria, such as Lactobacillus acidophilus and bifidobacterium longum. Unlike bacteria which causes disease, L. acidophilus and B. longum are extremely helpful. They produce digestive enzymes and assists in the final processing of food. They also produce important vitamins such as vitamin K and the B vitamins (B12, thiamine and riboflavin), and help inhibit the growth of harmful bacteria. Unfortunately, naturally occurring lactobacillus and bifidobacterium can be destroyed by a course of antibiotic treatment.