Atonic Colon Symptoms and Causes

Atonic colon (pronounced ay-TAW-nik KOH-lun) occurs when there is a lack of normal muscle tone or strength in the colon. Also, known as lazy colon or colon stasis, it may result in chronic constipation. When your intestines are backed up, as in constipation, it slows the rate in which your stomach can empty, which in turn may cause heartburn.

Hand reaching for toilet paper
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Atonic colon is essentially a "vicious circle" phenomena. Constipation can lead to reduced bowel activity, which in turn can lead to a worsening of constipation, and so on.


While the cause of atonic colon is often unknown, chronic laxative use can be to blame. A relatively rare cause is Hirschsprung's disease, which causes blockages in part or all of the large intestine due to a lack of nerve cells that are needed for normal muscle movement. But Hirschsprung's disease isn't something you can develop or catch, it is a congenital condition, which means that it is present from birth. It is also known as congenital megacolon.

With megacolon, the bowel becomes extremely dilated and atonic (not moving) with a large amount of stool "just sitting there."

The Science Behind It

In many ways, atonic colon is an example of classical conditioning. Simplistically, the colon begins to "give up" when a stimulus does not result in the evacuation of the bowel and stops responding to signals. This can be similar to a parent, who after hearing a child ask for something a few dozen times, begins to "not hear" the requests. In contrast, in conditions such as Hirschsprung's disease, the ganglia, or collection of nerves controlling this function are absent.

Link to Laxatives

Atonic colon is often seen as a side effect of laxative addiction. Laxatives work by stimulating the bowel muscles with irritants. However, when they are used repeatedly, the muscles build up a tolerance and larger quantities of the irritants are needed to get the same effect. This causes low muscle tone, which results in an atonic colon. When defecation can only occur with the use of a laxative, this is a laxative addiction.


Besides constipation, you may also experience stomach pains, bloating, nausea, vomiting, and fever. Whether you are experiencing any, some, or all of these symptoms, make an appointment to see your healthcare provider.

When to Talk to Your Healthcare Provider 

Discussing your bathroom habits can be almost as uncomfortable as constipation that you are experiencing. But when it is time to speak to your healthcare provider, it is time to be a partner in your care. Meaning, don't hide anything, especially if you have been using a laxative for an extended period of time. Also, try to do some pre-appointment work.

When trying to pinpoint the cause of your constipation, there are a few questions that your healthcare provider may ask you. Be prepared to answer the following:

  • How often do you have a bowel movement?
  • Have there been any changes in your bowel habits (i.e, frequency, ease)?
  • Have you noticed any change in the bulk of your stools?
  • Do you feel that you have emptied your bowels entirely after you go to the toilet?

And since constipation can be caused by other things besides an atonic colon, don't be surprised if your healthcare provider wants to talk about your mood — depression can trigger constipation; your sleeping patterns — medication given to treat insomnia can affect bowel movements ; your energy levels — if your thyroid isn't working properly (hypothyroidism), neither will your bowels; and your exercise habits — if you lead a sedentary lifestyle, this can also affect your output.

Possible Treatments

If laxatives are the cause of your lack of bowel muscle tone, they will not be used to combat chronic constipation you are experiencing. Instead, your healthcare provider may use enemas, or suggest bowel retraining. Another treatment that is sometimes used for chronic constipation, especially when the cause is closely related to the digestive system, is biofeedback.

Tips for Coping and Prevention

Understanding a bit about the science between bowel emptying can help explain what measures can help prevent constipation that can lead to atonic colon.

  • Listen to nature. The bowel is most active in the morning and following meals. The passing stool is easiest when your efforts combine with this physiology.
  • Make sure you have enough fiber in your diet (but not too much which can lead to pain, bloating, and other problems.) Fiber increases the water content of stool so that it moves easier through the gut. Fiber also increases the weight of stool, assisting in the gravity part of the equation.
  • Work with your healthcare provider to retrain your bowel habits.
  • Keep a defecation journal. Sometimes patterns become much clearer when they are spelled out in writing.
5 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.
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  2. National Institute of Diabetes and Digestive and Kidney Diseases. Hirschsprung Disease.

  3. Sparberg M. Constipation. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths. Chapter 89.

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Additional Reading

By Sharon Gillson
 Sharon Gillson is a writer living with and covering GERD and other digestive issues.