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What Is Diarrhea?

Diarrhea May Signal Colon Cancer, So Don't Just Ignore It


Updated June 02, 2014

Stomach ache
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Diarrhea usually isn't something you discuss at the dinner table, but if you're experiencing frequent, chronic, or intermittent diarrhea, don't remain silent about it. You should make an appointment with your doctor so that you can get to the bottom of your symptoms as quickly as possible.

Many things can cause diarrhea, from foodborne illness ("food poisoning") and viruses or bacteria that are passed from person to person, to food allergies and even use of some medications. But when diarrhea is frequent, has no apparent cause, and becomes a chronic problem, it may signal something more serious, such as colon cancer or inflammatory bowel disease.

The colon, also known as the large intestine, controls the formation and passage of solid waste (stool) from the body. The colon absorbs water out of the solid waste and uses muscles to move the waste along toward the rectum and anus for passage out of the body. The further along in your colon the waste goes, the less water it contains, until it forms a solid stool. When something disrupts this process (too little water is absorbed), diarrhea can result.

Diarrhea in the absence of any other symptoms may point to a cause other than colon cancer. However, if you have diarrhea accompanied by other possible symptoms of colon cancer, such as blood in your stools, pain, or bloating, this increases the chances that something more serious may be going on with your body.

Regardless of any accompanying symptoms, long-term diarrhea should not be ignored. Colon cancer is a disease that when found early, is highly curable, with long-term survival rates well over 90%. Unfortunately, if the cancer is more advanced, and has spread beyond the colon, survival rates drop dramatically. Err on the side of caution and don't wait to see your doctor

Your doctor may ask for a stool sample from you, so that he can check for infections due to bacteria, viruses, or parasites. A screening exam, such as a colonoscopy or flexible sigmoidoscopy, may be scheduled as well. If you are nervous about getting screened, you can educate yourself so you know what to expect and don't have to dread your screening test.

See Your Doctor If...

  • Your diarrhea has lasted for more than two weeks; it could be on and off or present the entire time
  • You see blood in or on your stool
  • You have persistent cramps or severe pain
  • You are vomiting
  • You experience alternating constipation and diarrhea
  • You have unexplained weight loss (losing weight when you are not trying)


American Cancer Society. Colon Cancer Accessed July 22, 2009. www.cancer.org/downloads/COM/05MarchPresentation.pdf

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