A large colony of various bacteria that inhabit the large intestine further digest food, releasing in the process some of the mineral compounds that dissolve in the water that is transported into the blood . Conditions that affect large intestine While the normal colony of bacteria in the large intestine contributes to absorption of nutrients from food, it frequently happens that certain species or strains of bacteria produce toxins that damage the walls of the intestine. The body reacts in several ways. Food wastes may be processed too quickly in an effort to rid the body of the irritating bacteria. When this happens, water is not removed because of the short time the wastes spend in the intestine.
Feces produced are thin and watery, a condition known as diarrhea .
Diarrhea also results if the inflammation of the walls of the intestine produces swelling that effectively seals the walls, keeping the fluids from passing through. Although bacteria are the source of toxic attacks on intestinal walls, viruses can also interfere with operation of the intestines by causing tissues to be inflamed and to swell up. In this case, the immune system is probably the actual cause of the symptoms as it tries to rid the body of the viral infection. Certain parasites, notably amoebas, also produce toxins or otherwise halt the operations of the large intestine. A common problem is giardia , in which a parasite attaches itself to the intestinal wall.