Constipation is the painful or difficult passing of food product waste (stool) through the anus. Stool may be hard, dry and painful to pass, or a person may need to strain in order to have a bowel movement. It may feel as if the bowels still need to be emptied, even after stool has been passed. Constipation may be accompanied by other symptoms, including gas, nausea, rectal pressure and abdominal pain, cramping or distention.
During normal digestion, food moves from the stomach to the small intestine, where nutrients are absorbed. By the time it gets to the colon (large intestine), only the waste material remains. The colon absorbs water from the waste and passes the stool along via muscle contractions (peristalsis) to the rectum at the end of the digestive tract.
Constipation occurs when waste material moves too slowly through the intestines and too much water is absorbed and stool becomes hard and difficult to pass.
The longer waste stays in the intestines, the more water is taken from it and reabsorbed into the body.
Many people believe that it is necessary to have a bowel movement every day. The belief that all waste must be eliminated from a person’s body in order to maintain health or cleanliness is also common. However, both are untrue. The frequency of bowel movements can vary greatly from person to person, and can range from three times a day to three times a week. The natural firmness of stool can also vary from person to person. Passing stool less than three times a week may indicate constipation.
At some point in their lives, most people experience constipation. It is one of the most common gastrointestinal complaints in the United States. Approximately 3 million Americans have frequent constipation, according to the National Institutes of Health (NIH).
Constipation is reported most often among adults age 65 and over. Seventy-five percent of elderly hospitalized patients and nursing home residents use laxatives to help regulate their bowel movements. Older adults may be overly concerned with a daily bowel movement, leading them to believe they have constipation when they do not. Older adults are also likely to take constipation-causing medications, have decreased levels of physical activity, and low-fiber, high-fat diets. All of these factors can contribute to constipation.
Constipation is also common following childbirth or surgery. People who learn to withhold their bowel movements by not acting on urges to defecate may also experience constipation. This may occur in children during toilet training, in adults with concerns about using public toilets or for other, varied reasons.
Constipation may be acute or chronic. The symptoms of acute constipation tend to begin suddenly and are very obvious. Chronic constipation occurs gradually and may last for longer periods of time. Chronic constipation can continue for months or years.
Constipation is usually short-lived. When it is not, it may be a symptom of a more serious medical condition. A physician should be notified when constipation lasts longer than three weeks or involves intense abdominal pain or blood in the stool. For most patients with constipation, the blood will appear maroon or bright red in color, indicating it is coming from the lower digestive tract (intestines, colon or rectum) – as is seen with hemorrhoids, anal fissures or diverticular bleeding. If the blood appears black, it may be originating from the upper digestive tract (mouth, esophagus or stomach). Peptic ulcers are a common cause of upper GI tract bleeding.
Potential complications of constipation
In most people, constipation occurs occasionally and has no lasting complications. However, chronic or severe constipation can potentially cause a variety of complications, including:
Hemorrhoids and/or anal fissures. Hemorrhoids can be caused by straining to have a bowel movement, which is often associated with constipation. Anal fissures may develop when hard food product waste (stool) stretches the anal sphincter. Blood may appear in the stool as a result of hemorrhoids or anal fissures, appearing as bright red streaks on the surface of the stool.
Rectal prolapse. Straining during a bowel movement can cause some of the intestinal lining to be pushed through the rectal opening.
Fecal impaction. Stool is considered impacted when it is packed tightly in the bowel and normal pushing is not enough to spontaneously expel the stool. Impaction can mimic diarrhea, with liquid stool flowing around the hard impaction. Fecal impaction tends to occur in very young children and in older adults.
Some of the conditions that can result from constipation may also cause or contribute to the problem. For more information, see Potential causes.
What causes constipation?
Constipation may be a symptom of a medical condition, side effect of a medication or the result of lifestyle choices. In addition, age-related factors, such as decreased activity of the intestinal muscles and enlargement of the rectum, can lead to constipation. Chronic pain and some mental disorders (such as depression) may also cause constipation. The most common causes of constipation are a low-fiber diet and a lack of exercise.
Digestive system disorders that can cause constipation include:
Irritable bowel syndrome (IBS)
Spasms in the colon that affect bowel movements. Contents travel slowly through the intestines in patients with IBS, which can lead to constipation. Patients with IBS often experience alternating episodes of constipation and diarrhea. IBS is one of the most common causes of chronic constipation in the United States.
Inflammation and tears around the anus that can cause bleeding, itching and/or pain. Patients with hemorrhoids or anal fissures may withhold stool due to these painful conditions, which may lead to constipation. In addition, hemorrhoids may produce muscle spasms in the anus, which can delay bowel movements, also causing constipation. On the other hand, patients with constipation may develop hemorrhoids or anal fissures by straining during bowel movements and the passage of hard, dry stools through the anus.
Compression or obstruction of the intestines
Pressure or tightening of the intestines (strictures) due to scar tissue, tumors, cancer or diverticulitis (inflammation around small pockets called diverticula). This narrowing or blockage can cause constipation.
Restricted ability or inability of intestinal muscles to contract, causing waste to move slowly through the intestines or not at all, which causes constipation. In colonic inertia, food product waste (stool) may remain stored in the middle portion of the colon rather than progressing through it, leading to constipation. Colonic inertia and delayed transit are two types of chronic idiopathic (of unknown origin) constipation that may be related to nerves, hormones or muscles in the colon, rectum or anus. These types of disorders are most common in women.
Poor coordination of pelvic and anal muscles. The inability to relax the pelvic floor muscles (that support the bladder, uterus and rectum) and anal sphincter (that keeps the anus closed) can cause constipation.
Uncontrolled growth of abnormal cells in the colon or rectum.
Some medicines may cause constipation. These include:
Diuretics (medicine that increases the production of urine)
Although they are sometimes used to treat constipation, laxatives can also cause constipation when used too often. Frequent use of laxatives can interfere with the colon’s natural ability to contract, leading to failure of the intestines to work properly and causing constipation. This is sometimes referred to as lazy bowel syndrome.
Diet or lifestyle issues that can cause constipation include:
Diet. A low-fiber diet (not enough fresh vegetables, fruits or whole grains) may lead to constipation. Because fiber is not digested by the body, it passes through the intestines virtually unchanged. Its soft texture adds bulk to stool, helping to move waste through the intestines. Soluble fiber (e.g., psyllium, oatmeal) turns to a gel when mixed in fluid. Insoluble fiber (e.g., whole grain breads and cereals) does not dissolve in liquid. Both types aid in relieving constipation. Foods high in fat and sugar (such as many soft, processed foods) can slow the digestive process, causing too much fluid to be absorbed from stool, and leading to constipation.
Suppressing the urge to have a bowel movement. Withholding or delaying the release of stool is sometimes done to avoid using public toilets, because it is inconvenient or because a person is busy. It can also occur as the result of severe emotional distress. However, repeatedly resisting the urge to defecate can lead to insensitivity of the intestines. The usual urges are no longer felt and constipation results.
Immobility or sedentary lifestyle. Exercise stimulates intestinal activity, helping to regulate bowel movements. A lack of exercise or too much bed rest can lead to constipation.
Travel. Changes in a person’s schedule, activity level or diet as the result of traveling may interrupt normal digestive processes and cause constipation.
Pregnancy. Hormonal changes that occur during pregnancy may play a role in causing constipation. Later in the pregnancy, added weight of the womb can increase pressure on the intestines, which can cause constipation.
Insufficient intake of fluids. Without enough fluids, the body will conserve water in the blood by removing additional water from the stool, leading to hard, dry stool. In addition, drinks containing caffeine (e.g., coffee, cola) or alcohol have a dehydrating effect and can lead to constipation.
Habitual use of enemas. Frequent enemas may damage nerve cells in the colon and interfere with the colon’s natural ability to contract. This can lead to a loss of normal functioning and include constipation.
Stress. Stress can slow digestion, increasing the amount of water absorbed from waste in the intestines, which can create hard, dry stool difficult to pass.
Loss of body salts. When too much salt is absorbed by the kidneys or lost via vomiting or diarrhea. Salt is necessary for the absorption of food in the intestines – too little salt in the body may cause constipation.
Problems outside the digestive tract may also cause constipation by slowing the movement of stool through the large intestine, causing too much fluid to be absorbed.
These conditions include:
Stroke (interruption in the flow of blood to the brain)
Spinal cord injuries (damage that affects nerves in the spinal cord)
Multiple sclerosis (nerve cell damage affecting the brain and spinal cord)
Parkinson’s disease (damage to the area of the brain that controls movement)
Diabetes (high levels of sugar in the blood)
Underactive thyroid (low levels of metabolism-stabilizing hormones)
Scleroderma (connective tissue disease that can harden skin)
Lupus (chronic inflammation caused by the body’s own immune system)
Eating disorders (may include laxative abuse)
Diagnosing causes of constipation
Most people with constipation will not need extensive testing. Testing is usually required in cases of severe or sudden constipation, when blood is found in the stool and/or for older adults.
Physicians often rely on a patient’s report of symptoms in diagnosing and determining treatment for constipation. A medical history will include questions about the duration and severity of symptoms. Current medications, eating habits and levels of physical activity may also be discussed.
Chronic constipation is suggested when any two of the following factors occurs for a total of 12 weeks (not necessarily consecutive) in the past year:
Straining during bowel movements
Sensation of incomplete defecation
Sensation of blockage or obstruction
Having less than three bowel movements per week
A physical examination may include a digital rectal examination. This involves use of a physician’s gloved, lubricated finger to evaluate the strength of anal sphincter, and to detect any tenderness, obstruction or blood in the area.
Additional tests that may be conducted when a patient has constipation include:
Fecal tests. Stool is tested for the presence of occult bleeding (subtle traces of blood not visible to the naked eye) that may indicate an underlying disease, such as colorectal cancer.
Blood tests. Blood is drawn and tested for evidence of thyroid or other disorders that may be causing the constipation.
Colorectal transit study. Patients swallow capsules containing small markers that can be visible when x-rays are taken three to seven days after the capsule is swallowed. This may be used in cases of chronic constipation to identify how well food moves through the colon.
Anorectal function tests. Used to identify dysfunction of the anus or rectum. Tests include a pressure-sensitive tube inserted into the anus to measure the muscle contractions in the anal sphincter and a defecography x-ray that can measure the completeness of defecation.
Barium enema x-ray. X-rays of the colon and rectum are taken after a patient has an enema of a chalky substance (barium) inserted into their bowel. The barium enables images of internal organs to show up clearly on x-ray. This method may be preferred if constipation is accompanied by rectal bleeding. Barium enema x-rays may be used to identify cancer, intestinal obstruction or Hirschsprung's disease (a birth defect that causes intestinal blockage) in patients with constipation.
Colonoscopy. A flexible tube (with light and camera attached) is inserted into the patient’s anus and through the entire colon. This method is used to identify any abnormalities, including whether colorectal cancer may be causing the constipation. A biopsy may be performed during this procedure and color pictures may be taken.
Sigmoidoscopy. Similar to a colonoscopy, although the tube is only inserted up to the lower part of the colon. May help identify problems in the rectum and lower colon in patients with constipation.
Treatment options for constipation
When constipation is a symptom of another medical condition, it is important to treat the underlying condition. Some conditions may not have a cure and may require ongoing treatment to manage symptoms, including constipation. Individual episodes of constipation can be treated in a number of ways.
Constipation that occurs without fecal impaction (and no underlying medical condition) is commonly treated with an increase in fluids, fiber and exercise. If changes in diet or physical activity are not effective, laxatives may be used. Patients should consult with their physician before using laxatives, which can interfere with the absorption of various medicines. In addition, overuse of laxatives can destroy the colon’s natural ability to contract and lead to dependence on laxatives.
Laxatives can be taken by mouth in liquid, pill, chewing gum or powder form. They are also available in suppository form for insertion into the anus, or can be used in an enema. In general, suppositories and enemas work more quickly than pills to restore normal bowel movement.
If constipation occurs with fecal impaction, the most common treatment is a tap-water enema. This flushes the stool from the rectum and lower part of the large intestine (colon). A physician may also use a gloved finger to manually remove the stool. The patient may first be asked to drink a solution of salt and polyethylene glycol, which helps clean the digestive system.
When constipation occurs with dyschezia (the inability to relax muscles around the rectum and anus), biofeedback may be used to help regain the ability to contract and release the anal sphincter. The surgical removal of the colon may be necessary with severe constipation caused by colonic inertia (when stool fails to be pushed through the large intestine and remains stored in the colon).
The prescription drug tegaserod (Zelnorm), which regulates bowel movements by affecting serotonin levels in the body, was used to treat constipation in patients with irritable bowel syndrome. However, the manufacturer agreed to discontinue marketing this medication in March 2007 due to a high incidence of adverse cardiovascular events. Patients currently taking this medication are urged to consult their physician.
Prevention methods for constipation
There is no way to guarantee the absence of constipation. However, there are many diet and lifestyle changes a person can make to help prevent constipation. In addition, patients with constipation may wish to check with their physician about medications they are currently taking, since some may cause constipation (e.g., iron supplements, antacids with calcium or aluminum, antidepressants, some pain pills). A physician may be able to recommend alternatives that do not cause or aggravate a patient’s constipation.
Diet and lifestyle tips to help prevent constipation include:
Exercise regularly. Exercise helps to stimulate intestinal activity, speeding the passage of food through the digestive system. Swimming, walking or other regular forms of exercise can help a person avoid constipation.
Eat a diet high in fiber. Fiber (whole-grain cereals and bread, beans, fresh fruits and vegetables) helps bulk up and soften stool, stimulating intestinal contractions that help move food through the digestive system. The American Dietetic Association recommends each person include 20 to 25 grams (0.7 to 1.2 ounces) of fiber a day in their diet – although most Americans eat 5 to 14 grams (0.2 to 0.5 ounces) of fiber a day, according to the National Center for Health Statistics. Gradually adding fiber to a diet can help to avoid problems with gas or bloating.
Take fiber supplements. These types of bulk-forming laxatives can help prevent constipation. Patients may attempt to counteract the effects of a constipation-causing medicine with laxatives, such as fiber supplements. However, patients should consult with a physician before using any type of laxative since some may be habit-forming and may interfere with the absorption of certain medications.
Avoid excessive fats and sugar. Foods high in fat and sugar may cause or aggravate constipation. Excess fat and carbohydrates can slow digestion, causing too much fluid to be absorbed from stool, making it hard and difficult to pass. On the other hand, patients who have problems absorbing fats and sugars may experience diarrhea, as stool becomes loose and greasy. Maintaining a balanced diet by avoiding excessive fats and sugar can help promote normal bowel function.
Maintain consistent eating times. Eating meals on a regular schedule (at close to the same time every day) can promote normal bowel functioning and help prevent constipation.
Use natural laxatives. Eating foods with natural laxative qualities (e.g., prunes, sauerkraut, green sprouts) can help prevent constipation.
Avoid foods that are intrinsically dry, such as crackers, breadsticks, nuts and bagels.
Drink plenty of fluids. Water and other fluids add bulk to stool, making bowel movements softer and easier to pass. The recommended daily amount of fluid is eight 8-ounce glasses. Caffeine (e.g., coffee, soda) and alcohol should be avoided since they have a dehydrating effect.
Do not ignore the urge to defecate. Recognizing and responding to the body’s signals to defecate can help prevent constipation. Bowel movements that are purposefully withheld or delayed may lead to hard, dry stool that is painful to pass.
Make time for bowel movements. Allowing sufficient time for undisturbed visits to the bathroom can help prevent constipation.
Questions for your doctor on constipation
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following constipation-related questions:
How often should I have a bowel movement? (What is normal for me?)
If I don’t have a bowel movement that often, does that mean I have constipation? How else can I tell if I am constipated?
At what point should I seek treatment for constipation?
What is the cause of my constipation?
Do I have any other medical conditions related to my constipation?
What type of treatment do you recommend?
What diet or lifestyle changes to prevent constipation would be most effective for me?
When should I consider laxative use to relieve my constipation? Which type do you recommend?
Are the medications I am taking contributing to my constipation? Are there alternatives that do not have this side effect?
Are there any symptoms related to constipation that I should immediately report to you?
I take Zelnorm for constipation associated with irritable bowel syndrome, but heard that it was recently discontinued. What are my options?
For occasional constipation, you may use stool softeners, mild non-prescription laxatives or enemas. Don't use laxatives or enemas regularly as this can cause dependency. Avoid harsh laxatives and cathartics, such as Epsom salts. The best laxatives are bulk-formers, such as bran, psyllium, polycarbophil and methylcellulose.
Regular exercise and good physical fitness help stimulate the bowel and maintain healthy bowel patterns.
Drink at least 8 glasses of water each day. Include bulk foods, such as bran and raw fruits and vegetables, in your diet. Avoid refined cereals and breads, pastries and sugar.
What might complicate it?
Individuals may experience urinary tract infections, urinary stones (bladder calculi), colon cancer, breast disease, and enlarged ureters (urethral dilation).
Most individuals can expect to return to normal bowel function. Individuals who continue to have problems with constipation may progress to more severe gastrointestinal symptoms.