What causes constipation?

Common causes of constipation include inadequate water intake, inadequate fiber intake, medication, stress and/or lack of activity or exercise. If you’ve strayed from your normal routine due to travel, pregnancy or simply ignoring the urge to go, that can also play a role.

In some people, constipation can keep coming back. As many as 35 million adults suffer from chronic idiopathic constipation (CIC), which is constipation without a known cause, and as many as 13 million adults suffer from irritable bowel syndrome with constipation (IBS-C), one of the three major subtypes of IBS.

In rare cases, constipation can signal something more serious, such as a bowel obstruction, hypothyroidism, neurological disease or cancer, so it’s important to get recurring constipation checked by your healthcare provider.
There are many causes of constipation, and each person and situation is different. Some of the most common causes include overuse of laxatives and enemas, medication taken after surgeries, decreased or a lack of abdominal muscle tone, insufficient amounts of fiber and bulk in the diet to cause bowel movements, dry and hard feces due to lack of moisture, poor bowel habits (not going often enough), nervousness, and anxiety. (This answer provided for NATA by the University of Montana Athletic Training Education Program.)
Lawrence S. Friedman, MD
Common causes of constipation include:

Lack of exercise. People who exercise regularly seldom complain about constipation. Basically, the colon responds to activity. Good muscle tone in general is important to regular bowel movements.

Medications. Constipation is a side effect of many prescription and over-the-counter drugs. These include pain medications (especially narcotics), antacids that contain aluminum, antispasmodics, antidepressants, tranquilizers and sedatives, bismuth salts, iron supplements, diuretics, anticholinergics, calcium-channel blockers, and anticonvulsants.

Irritable bowel syndrome (IBS). Some people who suffer from IBS have sluggish bowel movements, straining during bowel movements, and abdominal discomfort. Constipation may be the predominant symptom, or it may alternate with diarrhea; cramping, gas, and bloating are also common.

Abuse of laxatives. Laxatives are sometimes used inappropriately, for example, by people suffering from anorexia nervosa or bulimia. But for people with long-term constipation, the extended use of laxatives may be a reasonable solution.

Changes in life or routine. Pregnancy, for example, may cause women to become constipated because of hormonal changes or because the heavy uterus pushes on the intestine. Aging often affects regularity because slower metabolism can reduce intestinal activity and muscle tone. Traveling can give some people problems because it changes normal diet and daily routines.

Ignoring the urge. If you have to go, go. If you hold in a bowel movement, for whatever reason, you may be inviting a bout of constipation.

Not enough fiber and liquid in the diet. A diet too low in fiber and liquid and too high in fats can contribute to constipation. Fiber absorbs water and causes stools to be larger, softer, and easier to pass. Increasing fiber intake helps cure constipation in many patients.

Other causes of constipation. Diseases that can cause constipation include neurological disorders, such as Parkinson's disease, spinal cord injury, stroke, or multiple sclerosis; metabolic and endocrine disorders, such as hypothyroidism, diabetes, or long-term kidney disease; bowel cancer; and diverticulitis. A number of systemic conditions, like scleroderma, can also cause constipation. In addition, intestinal obstructions, caused by scar tissue from an operation or strictures of the colon or rectum, can compress, squeeze, or narrow the intestine and rectum, causing constipation.
Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)

What you eat can make a big difference in whether or not you are constipated.

Watch the video to learn more from Dr. Oz about what causes constipation and what you can eat to relieve it.

There are two primary causes of constipation. When food is digested, it passes through the colon, or large intestine, which absorbs essential fluids. If the colon absorbs too much water, this causes the stools to become hard and dry and difficult to pass. Constipation is also caused by disturbances in the muscles that aid in digestion. If these muscles are not relaxed, it is difficult or impossible to pass stools. Other factors can cause constipation, including poor diet, lack of physical activity, inadequate fluid intake, dairy products, irritable bowel syndrome, pregnancy, aging, ignoring the urge to have a bowel movement, colon problems, rectal problems, stroke or other conditions, travel, abuse of laxatives, and the use of certain types of drugs.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.