The colon responds strongly to stimuli (for example, foods or stress) that would not bother most people intolerance-lactose-intolerence The colon, which is about 5 feet long, connects the small intestine with the rectum and anus intolerance-lactose-intolerence The major function of the colon is to absorb water, nutrients, and salts from the the partially digested food that enters from the small intestine intolerance-lactose-intolerence Two pints of liquid matter enter the colon from the small intestine each day intolerance-lactose-intolerence Stool volume is a third of a pint intolerance-lactose-intolerence The difference in volume represents what the colon absorbs each day intolerance-lactose-intolerence The following have been been associated with a worsening of IBS symptoms: The lining of the colon (epithelium) , which is affected by the immune and nervous systems, regulates the passage of fluids in and out of the colon intolerance-lactose-intolerence In IBS, the epithelium appears to work properly intolerance-lactose-intolerence However, fast movement of the colon's colon's contents can overcome the absorptive capacity of the colon intolerance-lactose-intolerence The result is too much fluid in the stool intolerance-lactose-intolerence In other patients, colonic movement is too slow, too much fluid is absorbed, and constipation develops intolerance-lactose-intolerence The NIDDK conducts and supports research into many kinds of digestive disorders, including including IBS intolerance-lactose-intolerence Researchers are studying gastrointestinal motility and sensitivity to find possible treatments for IBS intolerance-lactose-intolerence These studies include the structure and contraction of gastrointestinal muscles as well as the mechanics of fluid movement through the intestines intolerance-lactose-intolerence Understanding the influence of the nerves, hormones, and inflammation in IBS may may lead to new treatments to better control the symptoms intolerance-lactose-intolerence The normal motility of the colon may not work properly intolerance-lactose-intolerence It can be spasmodic or can even stop temporarily intolerance-lactose-intolerence Spasms are sudden strong muscle contractions that come and go intolerance-lactose-intolerence What are the symptoms of IBS? What causes causes one person to have IBS and not another? No one knows intolerance-lactose-intolerence Symptoms cannot be traced to a single organic cause intolerance-lactose-intolerence Research suggests that people with IBS seem to have a colon that is more sensitive and reactive than usual to a variety of things, including certain foods and and stress intolerance-lactose-intolerence Some evidence indicates that the immune system, which fights infection, is also involved intolerance-lactose-intolerence IBS symptoms result from the following: What does the colon do? What is the treatment for IBS? wheat, rye, barley, chocolate, milk products, or alcohol When it starts, there is a change in how how often you have a bowel movement intolerance-lactose-intolerence When it starts, there is a change in the form of the stool or the way it looks intolerance-lactose-intolerence With any medication, even over-the-counter medications such as laxatives and fiber supplements, it is important to follow your doctor's instructions intolerance-lactose-intolerence Laxatives can be | 