Constipation | Causes & Risk Factors


What causes constipation?

Usually, constipation occurs when stool passes too slowly through your intestines. This causes the stool to become hard and dry. A number of things can cause your intestines to slow down, including:

  • Not enough fiber in your diet: The American Dietetic Association recommends that adults eat 20 to 35 grams of fiber each day. Most people get much less than this. See the Treatment section to learn how to get more fiber in your diet.
  • Not enough liquids in your diet: Liquids add fluid to the intestine and make up part of the stool. If you don’t drink enough liquids, your stool may dry out faster.
  • Not enough physical activity: Doctors don’t know why, but getting regular exercise seems to help your intestines work properly.
  •  Ignoring the urge to have a bowel movement: If you regularly ignore the urge to have a bowel movement, you may eventually stop feeling the need to have one. This can cause stool to build up in the intestine, making for a larger stool that is harder to pass.
  • Medicines: Certain medicines may cause constipation. This is very common with opiate pain medication, for example. If you notice that your constipation occurs after taking a new medicine, talk to your doctor. Using laxatives often may also lead to constipation. When you use laxatives often, you can become dependent on them. This means you have to take the laxative in order for your intestines to work like they should.
  • Life changes or changes in your daily routine: Life events such as pregnancy and aging, and changes in routine, such as travel, may cause constipation.
  • Intestinal problems: Intestinal problems such as obstruction, tumors, irritable bowel syndrome, or pelvic floor dysfunction, may cause constipation.
  • Certain diseases: Certain diseases, such as multiple sclerosis, stroke, diabetes, hypothyroidism, and lupus, also may cause constipation.

What causes constipation in children?

Constipation in children is caused by many of the same things that cause adults to have it (see list above). For example, it is likely to happen when your child doesn't drink enough water, milk, or other fluids, or if your child doesn't eat a healthy diet that includes enough fiber.

Constipation may also begin when you switch your baby from breast milk or baby formula to whole cow's milk, and when you switch from baby food to solid food. Sometimes constipation happens after your child has been sick or has taken certain medicines. You should not be concerned if your child becomes constipated for a short period of time. Constipation is common in children and usually goes away on its own.

Young children who have chronic constipation often ignore the urge to have a bowel movement. Your child may not want to interrupt play, or may be afraid or embarrassed to ask a teacher or use a public restroom. When a child avoids bowel movements, stool builds up in the lower bowel. The stool becomes larger and harder. Passage of the stool can be painful and makes children want to avoid having a bowel movement even more.


See a list of resources used in the development of this information.

Written by editorial staff

Reviewed/Updated: 08/12
Created: 08/96