10 Interesting Facts About Your Colon

How long it is, what's living in there, and why it's never empty

Your colon plays a vital role in digestion. It's an important part of your gastrointestinal (GI) tract, which makes up the digestive system.

By the time food reaches the colon, it's already through most of the digestion process. The colon's main role is to absorb water, vitamins, and electrolytes from partially digested food after it goes through the small intestine. Then, your colon prepares your body to get rid of the waste by passing stool (poop).

Taking the mystery out of your colon will help you better identify signs of common colon problems and help you feel more comfortable talking about this hard-working body part with your healthcare provider.

The following facts will help re-acquaint you with your colon. You'll learn where your colon is, how long your intestines are, the function of the large intestine, and even how much poop is in your body.


The Colon is 5 Feet Long

Male large intestine anatomy, illustration

Your colon, or large intestine, stretches from the end of your small intestine to your anus. In order, the parts of the large intestine are:

  • Cecum
  • Ascending colon
  • Transverse colon
  • Descending colon
  • Sigmoid colon
  • Rectum
  • Anal canal

The large intestine is about five feet long and forms an inverted U-shape around your abdomen. Your colon is three inches wide at its widest point, the cecum. It's just under an inch wide at its narrowest point, the sigmoid colon.


Colon Transit Time Is 12 to 48 Hours

Wall clock
Michael Skoglund / Getty Images

Many people believe the food they eat comes out in their next bowel movement. It actually takes a long time for food to make its way through the entire length of your digestive system.

This length of time is known as transit time and can be measured with a colonic transit time test.

Average transit times vary depending on the person. Factors that affect transit time include:

  • Race
  • Sex
  • Typical diet
  • Amount of physical activity

Transit time longer than 72 hours can be a sign of a bowel disorder.


Bowel Movement Frequency Varies

man outside a public rest room
Peter Dazeley/Photographer's Choice/Getty Images

Some people consider one bowel movement per day to be normal. But research doesn't support this. The frequency of bowel movements varies widely among individuals and varies widely for any single individual.


100 Trillion Microbes Live in Your Colon

illustration of various bacteria
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Our colons are host to trillions of microorganisms known as microbiota or gut flora. The majority of these organisms are bacteria.

The identification of the role of the microbiota led to the popularity of using probiotics as supplements and food additives to enhance digestive health and immune function.


Your Colon Is Never Empty

row of glasses with various amounts of water
Larry Washburn/Getty Images

Many people believe they have emptied out their colons after multiple episodes of diarrhea or that they can keep their colons empty by avoiding food. However, since stool is made up in large part of bacteria, fecal matter is continuously being formed.

Stool is made up of:

  • Bacteria
  • Liquid
  • Undigested food
  • Dietary fiber
  • Fat
  • Minerals
  • Protein

How Much Does Poop Weigh?

The weight of poop varies from person to person. However, adults generally excrete about 128 grams, or 0.25 pounds, of poop every day.


Your Rectum Is Usually Empty

empty box on table
Richard Drury/Stone/Getty Images

The muscles that line the descending and the sigmoid colons move fecal matter into the rectum at periodic intervals. In response, the rectum expands and holds onto the stool.

Your internal and external sphincter muscles contain the stool within the rectum. Once you decide to have a bowel movement, voluntary and involuntary muscles work together to expel the stool.


The Colon Absorbs 1 Quart of Water a Day

Close-Up Of Glass Jar On Table At Restaurant
Bernard Van Berg / EyeEm / Getty Images

It's the colon's job to complete the process of digestion. Its main purpose is to absorb water and electrolytes from the material passed from the small intestine. This material is then formed into a stool that can be passed during the process of a bowel movement.

When a person experiences diarrhea, they are passing stool that has not been in the colon long enough to have had enough liquid absorbed to firm up the stool.

The opposite occurs when a person experiences constipation. In that case, the stool has been in the colon too long and becomes dried out, hard, and difficult to pass.


Meals Can Trigger a Bowel Movement

Dagwood sandwich, close-up
Tom Grill / Getty Images

One of your body's reflexes is the gastrocolic reflex. When you eat something, this reflex kicks in and starts a process of movement throughout your entire digestive tract.

Large meals and fatty meals appear to cause a greater gastrocolic reflex and may prompt the need to poop. This information is useful for those who are prone to either constipation or diarrhea.

For the person with constipation, healthy fats (e.g., certain oils and polyunsaturated fats) are known to aid with constipation. However, foods high in saturated fat, such as hard cheeses, can be constipating. The person prone to diarrhea should stick to small, low-fat meals.


Healthy Stools Are Not Always Brown

group of colorful stools
Leslee Mitchell/Moment/Getty Images

There's no need to panic if you see some variation in the color of your stools. Various factors can affect stool color. Healthy stools typically fall into the brown range but can be yellow or orange as well.

Notify your healthcare provider if your stools are bright or dark red, or black or tar-colored. This may be a sign of internal bleeding.


You Can Live Without a Colon

Nothing beats the company of good friends!
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The nutrients from food that are essential for survival are mainly absorbed by your small intestine. Therefore, a person can have their colon removed and continue to have a healthy life.

Some health conditions, like colon cancer or inflammatory bowel disease, may make it necessary to remove a person's colon. In some of these cases, a procedure called a colostomy is done. During the procedure, an opening is made in the abdomen so that fecal material can be collected outside of the body in a colostomy bag.

Another option is the use of a J-Pouch, in which the last part of the small intestine is used to hold stool internally.

Frequently Asked Questions

  • Where is your colon?

    It's in your lower abdomen. The colon starts at the end of the small intestine and connects to the rectum.

  • How long are your intestines?

    Together, the small and large intestines measure about 27 feet. The small intestine is about 22 feet and the large intestine runs about 5 feet.

  • What are common colon problems?

    Diseases that affect your colon include irritable bowel syndrome (IBS), Crohn’s disease, ulcerative colitis, diverticulitis, colonic polyps, and colorectal cancer.

  • How do you know if you have problems with your colon?

    Symptoms of a colon-related condition may include abdominal pain and cramps, pain the lower left side of the abdomen, changes in your bowel patterns, diarrhea, constipation, bloating, or blood in the stool.

  • What are the odds you could get colon cancer?

    The chances are one in 23 for men (4.3%) and one in 25 for women (4%). About 90% of diagnoses are in people over age 50. Your risk is higher if you're overweight or obese, were previously diagnosed with colon polyps, or if you're African-American.

  • Do colon cleanses work?

    Commercial and fad treatments for colon cleansing are not proven to be effective and may harm your colon and other organs.

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institute of Diabetes and Digestive and Kidney Diseases. Your digestive system and how it works.

  2. National Cancer Institute: SEER Training Modules. Anatomy of colon and rectum.

  3. Icahn School of Medicine at Mount Sinai. Bowel transit time.

  4. Cleveland Clinic. Frequent bowel movements.

  5. Valdes AM, Walter J, Segal E, Spector TD. Role of the gut microbiota in nutrition and health. BMJ. 2018;361:k2179. doi:10.1136/bmj.k2179

  6. Rose C, Parker A, Jefferson B, Cartmell E. The characterization of feces and urine: a review of the literature to inform advanced treatment technologyCrit Rev Environ Sci Technol. 2015;45(17):1827-1879. doi:10.1080/10643389.2014.1000761

  7. Deiteren A, Camilleri M, Burton D, McKinzie S, Rao A, Zinsmeister AR. Effect of meal ingestion on ileocolonic and colonic transit in health and irritable bowel syndromeDig Dis Sci. 2010;55(2):384–391. doi:10.1007/s10620-009-1041-8

  8. NYU Langone Hospitals. Surgery for inflammatory bowel disease in adults.

  9. UPMC Children’s Hospital of Pittsburgh. Difference between small and large intestine.

  10. National Institutes of Health. Colonic diseases.

  11. American Cancer Society. Key statistics for colorectal cancer.

  12. Mishori R, Otubu A, Jones AA. The dangers of colon cleansingJ Fam Pract 2011;60:454–6.

By Barbara Bolen, PhD
Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome.