You likely already know that the colon is the large intestine. But it might surprise you to find out what the colon does and what can happen if you develop a colon-related condition.

The colon is one of the parts of your digestive system that helps absorb water and minerals and eliminate waste. In addition to the colon, the digestive system consists of the mouth, esophagus, stomach, and small intestine. Each part of the digestive system has a unique role in breaking down and absorbing calories and nutrients from food. This is vital to the proper function of your body.

Picture the colon as a long tube-like structure curled in your abdominal cavity. On average, an adult colon is about five to six feet long. On one end, the colon connects to the small intestine. The opposite end of the colon is connected to the rectum.

After you eat, involuntary muscle contractions, called peristalsis, move food through the digestive system. The body absorbs nutrients and calories as the food moves through the small intestine. Leftover waste material, which is mostly liquid, then travels to the colon. The colon removes water from the stool and balances electrolytes and pH.

Bacteria in the colon help the digestive process. Peristalsis continues to move the stool to the rectum, so that it can be eliminated during a bowel movement. It takes about 36 hours for food to work its way through your digestive system and pass from your stomach to your rectum.

Bacteria in the colon serve important functions, including:

  • synthesizing certain vitamins
  • protecting the body from harmful microorganisms
  • processing remaining food particles
  • maintaining proper pH

Although the colon is one large organ, it’s divided into four regions:

  • Ascending
    The ascending colon is located
    on the right side of the body. In the ascending colon, bacteria synthesize
    vitamins that remain in the stool.
  • Transverse
    The transverse segment of the colon
    is located between the ascending and descending colon. It crosses the abdominal
    cavity and runs from right to left. It’s the largest section of the colon.
    Water absorption continues to occur in the transverse colon.
  • Descending
    The descending colon sits
    between the transverse colon and the sigmoid colon. It’s usually located on the
    left side of the abdominal cavity.
  • Sigmoid colon: The sigmoid colon is the last region of the colon. It’s
    connected to the descending colon and the rectum. The sigmoid colon holds the
    stool until it moves into the rectum for elimination.

A healthy colon is essential to an efficiently working digestive system and overall good health. When one segment of your digestive system isn’t working correctly, it can interfere with the overall process of breaking down food and removing waste from the body.

For example, when your colon is not functioning as it should, stool can become too hard and constipation may result. Constipation can leave you feeling uncomfortable and bloated. It can also cause anal fissures and hemorrhoids.

The opposite can also occur. If water isn’t absorbed in the colon, diarrhea can develop. Diarrhea can lead to a loss of electrolytes, such as sodium, magnesium, and potassium. An imbalance in electrolytes can cause problems, such as dehydration, irregular heartbeats, muscle weakness, and in severe cases even death.

You might not give much thought to your colon until you have a problem. But there are several colon-related conditions that can have negative effects on your digestive health.

Some conditions associated with the colon are considered functional disorders. For this type of disorder, the colon may not function normally, but it doesn’t look abnormal. In other instances, the colon won’t function or appear normal.

Colon-related conditions can also lead to other problems throughout the body. Common colon-related conditions include:


Diverticula are small, bulging pouches or sacs that develop in the inner lining of the colon and grow though the muscular layer of the colon. When the pouches become inflamed, the condition is called diverticulitis. Although the pouches can occur in any segment of the colon, they most frequently occur in the sigmoid colon.

Symptoms of diverticulitis may include abdominal pain or tenderness, decreased appetite, and nausea. A serious complication that can occur with diverticulitis is peritonitis. This can develop if an inflamed pouch ruptures and spills intestinal material into your abdomen.

Crohn’s disease

Crohn’s disease is a long-term or chronic condition that causes swelling of the digestive tract. Although it often affects the small intestine, Crohn’s disease can also affect the colon. Symptoms include abdominal cramps, diarrhea, and fatigue.

Complications of Crohn’s disease can include malnutrition, ulcers, and a bowel obstruction. The condition can also affect other parts of your body. In some cases, Crohn’s disease triggers an immune system response that leads to inflammation of the skin, eyes, and joints.

Ulcerative colitis

Ulcerative colitis causes inflammation and sores in the inner lining of the colon. The severity of the disease may depend on how much of the colon is affected. Symptoms may include abdominal pain, weight loss, and fever. Additional symptoms may also occur, such as diarrhea, fatigue, and rectal bleeding.

The effects of ulcerative colitis can reach beyond the digestive tract. Complications of ulcerative colitis can include severe bleeding, bone loss, and in some cases liver disease.

Colon cancer

Colon cancer occurs when cells in the body grow out of control. At the time of diagnosis, cancer may be confined to a localized area or grow through the wall of the colon. In some cases, colon cancer can spread to distant areas of the body, such as the liver or lungs. Symptoms of colon cancer include changes in bowel habits, blood in the stool, and abdominal pain.