Constipation is passage of small amounts of hard, dry bowel
movements, usually fewer than three times a week. People who are constipated may
find it difficult and painful to have a bowel movement. Other symptoms of
constipation include feeling bloated, uncomfortable, and sluggish.
Many people think they are constipated when, in fact, their bowel movements are
regular. For example, some people believe they are constipated, or irregular, if
they do not have a bowel movement every day. However, there is no right number
of daily or weekly bowel movements. Normal may be three times a day or three
times a week depending on the person. Also, some people naturally have firmer
stools than others.
At one time or another, almost everyone gets constipated. Poor diet and lack of
exercise are usually the causes. In most cases, constipation is temporary and
not serious. Understanding its causes, prevention, and treatment will help most
people find relief.
According to the 1996 National Health Interview Survey, about
3 million people in the United States have frequent constipation. Those
reporting constipation most often are women and adults age 65 and over. Pregnant
women may have constipation, and it is a common problem following childbirth or
Constipation is one of the most common gastrointestinal complaints in the United
States, resulting in about 2 million doctor visits annually. However, most
people treat themselves without seeking medical help, as is evident from the
millions of dollars Americans spend on laxatives each year.
What causes constipation?
To understand constipation, it helps to know how the colon
(large intestine) works. As food moves through the colon, it absorbs water while
forming waste products, or stool. Muscle contractions in the colon push the
stool toward the rectum. By the time stool reaches the rectum, it is solid
because most of the water has been absorbed.
The hard and dry stools of constipation occur when the colon absorbs too much
water or if the colon's muscle contractions are slow or sluggish, causing the
stool to move through the colon too slowly. Common causes of constipation are:
- not enough fiber in the diet
- not enough liquids
- lack of exercise
- irritable bowel syndrome
- changes in life or routine such as pregnancy, older age,
- abuse of laxatives
- ignoring the urge to have a bowel movement
- specific diseases such as stroke (by far the most common)
- problems with the colon and rectum
- problems with intestinal function (chronic idiopathic
Not Enough Fiber in the Diet
The most common cause of constipation is a diet low in fiber
found in vegetables, fruits, and whole grains and high in fats found in cheese,
eggs, and meats. People who eat plenty of high-fiber foods are less likely to
Fiber—both soluble and insoluble—is the part of fruits, vegetables, and grains
that the body cannot digest. Soluble fiber dissolves easily in water and takes
on a soft, gel-like texture in the intestines. Insoluble fiber passes through
the intestines almost unchanged. The bulk and soft texture of fiber help prevent
hard, dry stools that are difficult to pass.
According to the National Center for Health Statistics, Americans eat an average
of 5 to 14 grams of fiber daily,* short of the 20 to 35 grams recommended by the
American Dietetic Association. Both children and adults eat too many refined and
processed foods from which the natural fiber has been removed.
A low-fiber diet also plays a key role in constipation among older adults, who
may lose interest in eating and choose convenience foods low in fiber. In
addition, difficulties with chewing or swallowing may force older people to eat
soft foods that are processed and low in fiber.
*National Center for Health Statistics. Dietary Intake of
Macronutrients, Micronutrients, and Other Dietary Constituents: United States,
1988–94. Vital and Health Statistics, Series 11, number 245. July 2002.
Not Enough Liquids
Liquids like water and juice add fluid to the colon and bulk
to stools, making bowel movements softer and easier to pass. People who have
problems with constipation should drink enough of these liquids every day, about
eight 8-ounce glasses. Liquids that contain caffeine, like coffee and cola
drinks, and alcohol have a dehydrating effect.
Lack of Exercise
Lack of exercise can lead to constipation, although doctors do
not know precisely why. For example, constipation often occurs after an accident
or during an illness when one must stay in bed and cannot exercise.
Some medications can cause constipation. They include:
- pain medications (especially narcotics)
- antacids that contain aluminum and calcium
- blood pressure medications (calcium channel blockers)
- antiparkinson drugs
- iron supplements
Irritable Bowel Syndrome (IBS)
Some people with IBS, also known as spastic colon, have spasms
in the colon that affect bowel movements. Constipation and diarrhea often
alternate, and abdominal cramping, gassiness, and bloating are other common
complaints. Although IBS can produce lifelong symptoms, it is not a
life-threatening condition. It often worsens with stress, but there is no
specific cause or anything unusual that the doctor can see in the colon.
Changes in Life or Routine
During pregnancy, women may be constipated because of hormonal
changes or because the heavy uterus compresses the intestine. Aging may also
affect bowel regularity because a slower metabolism results in less intestinal
activity and muscle tone. In addition, people often become constipated when
traveling because their normal diet and daily routines are disrupted.
Abuse of Laxatives
Myths about constipation have led to a serious abuse of
laxatives. This is common among people who are preoccupied with having a daily
Laxatives usually are not necessary and can be habit-forming. The colon begins
to rely on laxatives to bring on bowel movements. Over time, laxatives can
damage nerve cells in the colon and interfere with the colon's natural ability
to contract. For the same reason, regular use of enemas can also lead to a loss
of normal bowel function.
Ignoring the Urge to Have a Bowel Movement
People who ignore the urge to have a bowel movement may
eventually stop feeling the urge, which can lead to constipation. Some people
delay having a bowel movement because they do not want to use toilets outside
the home. Others ignore the urge because of emotional stress or because they are
too busy. Children may postpone having a bowel movement because of stressful
toilet training or because they do not want to interrupt their play.
Diseases that cause constipation include neurological
disorders, metabolic and endocrine disorders, and systemic conditions that
affect organ systems. These disorders can slow the movement of stool through the
colon, rectum, or anus.
Several kinds of diseases can cause constipation:
- multiple sclerosis
- Parkinson's disease
- chronic idiopathic intestinal pseudo-obstruction
- spinal cord injuries
Metabolic and endocrine conditions
- underactive or overactive thyroid gland
Problems with the Colon and Rectum
Intestinal obstruction, scar tissue (adhesions),
diverticulosis, tumors, colorectal stricture, Hirschsprung's disease, or cancer
can compress, squeeze, or narrow the intestine and rectum and cause
Problems with Intestinal Function (Chronic Idiopathic
Some people have chronic constipation that does not respond to
standard treatment. This rare condition, known as idiopathic (of unknown origin)
chronic constipation may be related to problems with intestinal function such as
problems with hormonal control or with nerves and muscles in the colon, rectum,
or anus. Functional constipation occurs in both children and adults and is most
common in women.
Colonic inertia and delayed transit are two types of functional constipation
caused by decreased muscle activity in the colon. These syndromes may affect the
entire colon or may be confined to the lower or sigmoid colon.
Functional constipation that stems from abnormalities in the structure of the
anus and rectum is known as anorectal dysfunction, or anismus. These
abnormalities result in an inability to relax the rectal and anal muscles that
allow stool to exit.
What diagnostic tests are used?
Most people with constipation do not need extensive testing
and can be treated with changes in diet and exercise. For example, in young
people with mild symptoms, a medical history and physical examination may be all
the doctor needs to suggest successful treatment. The tests the doctor performs
depend on the duration and severity of the constipation, the person's age, and
whether blood in stools, recent changes in bowel movements, or weight loss have
The doctor may ask a patient to describe his or her
constipation, including duration of symptoms, frequency of bowel movements,
consistency of stools, presence of blood in the stool, and toilet habits (how
often and where one has bowel movements). A record of eating habits, medication,
and level of physical activity or exercise will also help the doctor determine
the cause of constipation.
The clinical definition of constipation is any two of the following symptoms for
at least 12 weeks (not necessarily consecutive) in the previous 12 months:
- straining during bowel movements
- lumpy or hard stool
- sensation of incomplete evacuation
- sensation of anorectal blockage/obstruction
- fewer than three bowel movements per week
A physical exam may include a rectal exam with a gloved,
lubricated finger to evaluate the tone of the muscle that closes off the anus
(anal sphincter) and to detect tenderness, obstruction, or blood. In some cases,
blood and thyroid tests may be necessary to look for thyroid disease and serum
calcium or to rule out inflammatory, neoplastic, metabolic, and other systemic
Extensive testing usually is reserved for people with severe symptoms, for those
with sudden changes in number and consistency of bowel movements or blood in the
stool, and for older adults. Additional tests that may be used to evaluate
- colorectal transit study
- anorectal function tests
Because of an increased risk of colorectal cancer in older
adults, the doctor may use tests to rule out a diagnosis of cancer, including:
- barium enema x ray
- sigmoidoscopy or colonoscopy
Colorectal transit study. This test, reserved for those
with chronic constipation, shows how well food moves through the colon. The
patient swallows capsules containing small markers that are visible on an x ray.
The movement of the markers through the colon is monitored with abdominal x rays
taken several times 3 to 7 days after the capsule is swallowed. The patient
follows a high-fiber diet during the course of this test.
Anorectal function tests. These tests diagnose
constipation caused by abnormal functioning of the anus or rectum (anorectal
function). Anorectal manometry evaluates anal sphincter muscle function. For
this test, a catheter or air-filled balloon inserted into the anus is slowly
pulled back through the sphincter muscle to measure muscle tone and
Defecography is an x ray of the anorectal area that evaluates completeness of
stool elimination, identifies anorectal abnormalities, and evaluates rectal
muscle contractions and relaxation. During the exam, the doctor fills the rectum
with a soft paste that is the same consistency as stool. The patient sits on a
toilet positioned inside an x ray machine and then relaxes and squeezes the anus
to expel the paste. The doctor studies the x rays for anorectal problems that
occurred as the paste was expelled.
Barium enema x ray.This exam involves viewing the rectum, colon, and
lower part of the small intestine to locate any problems. This part of the
digestive tract is known as the bowel. This test may show intestinal obstruction
and Hirschsprung's disease, a lack of nerves within the colon.
The night before the test, bowel cleansing, also called bowel prep, is necessary
to clear the lower digestive tract. The patient drinks a special liquid to flush
out the bowel. A clean bowel is important, because even a small amount of stool
in the colon can hide details and result in an incomplete exam.
Because the colon does not show up well on x rays, the doctor fills it with
barium, a chalky liquid that makes the area visible. Once the mixture coats the
inside of colon and rectum, x rays are taken that reveal their shape and
condition. The patient may feel some abdominal cramping when the barium fills
the colon, but usually feels little discomfort after the procedure. Stools may
be a whitish color for a few days after the exam.
Sigmoidoscopy or colonoscopy. An examination of the rectum and lower
(sigmoid) colon is called a sigmoidoscopy. An examination of the rectum and
entire colon is called a colonoscopy.
The patient usually has a liquid dinner the night before a sigmoidoscopy and
takes an enema early the next morning. A light breakfast and a cleansing enema
an hour before the test may also be necessary.
To perform a sigmoidoscopy, the doctor uses a long, flexible tube with a light
on the end called a sigmoidoscope to view the rectum and lower colon. First, the
doctor examines the rectum with a gloved, lubricated finger. Then, the
sigmoidoscope is inserted through the anus into the rectum and lower colon. The
procedure may cause a mild sensation of wanting to move the bowels and abdominal
pressure. Sometimes the doctor fills the colon with air to get a better view.
The air may cause mild cramping.
To perform a colonoscopy, the doctor uses a flexible tube with a light on the
end called a colonoscope to view the entire colon. This tube is longer than a
sigmoidoscope. The same bowel cleansing used for the barium x ray is needed to
clear the bowel of waste. The patient is lightly sedated before the exam. During
the exam, the patient lies on his or her side and the doctor inserts the tube
through the anus and rectum into the colon. If an abnormality is seen, the
doctor can use the colonoscope to remove a small piece of tissue for examination
(biopsy). The patient may feel gassy and bloated after the procedure.
How is constipation treated?
Although treatment depends on the cause, severity, and
duration, in most cases dietary and lifestyle changes will help relieve symptoms
of constipation and help prevent it.
A diet with enough fiber (20 to 35 grams each day) helps form
soft, bulky stool. A doctor or dietitian can help plan an appropriate diet.
High-fiber foods include beans, whole grains and bran cereals, fresh fruits, and
vegetables such as asparagus, brussels sprouts, cabbage, and carrots. For people
prone to constipation, limiting foods that have little or no fiber, such as ice
cream, cheese, meat, and processed foods, is also important.
Other changes that can help treat and prevent constipation
include drinking enough water and other liquids such as fruit and vegetable
juices and clear soups, engaging in daily exercise, and reserving enough time to
have a bowel movement. In addition, the urge to have a bowel movement should not
Most people who are mildly constipated do not need laxatives.
However, for those who have made diet and lifestyle changes and are still
constipated, doctors may recommend laxatives or enemas for a limited time. These
treatments can help retrain a chronically sluggish bowel. For children,
short-term treatment with laxatives, along with retraining to establish regular
bowel habits, also helps prevent constipation.
A doctor should determine when a patient needs a laxative and which form is
best. Laxatives taken by mouth are available in liquid, tablet, gum, powder, and
granule forms. They work in various ways:
- Bulk-forming laxatives generally are considered the
safest but can interfere with absorption of some medicines. These laxatives,
also known as fiber supplements, are taken with water. They absorb water in
the intestine and make the stool softer. Brand names include Metamucil,
Citrucel, Konsyl, and Serutan.
- Stimulants cause rhythmic muscle contractions in the
intestines. Brand names include Correctol, Dulcolax, Purge, and Senokot.
Studies suggest that phenolphthalein, an ingredient in some stimulant
laxatives, might increase a person's risk for cancer. The Food and Drug
Administration has proposed a ban on all over-the-counter products containing
phenolphthalein. Most laxative makers have replaced or plan to replace
phenolphthalein with a safer ingredient.
- Stool softeners provide moisture to the stool and
prevent dehydration. These laxatives are often recommended after childbirth or
surgery. Products include Colace and Surfak.
- Lubricants grease the stool enabling it to move
through the intestine more easily. Mineral oil is the most common example.
- Saline laxatives act like a sponge to draw water
into the colon for easier passage of stool. Laxatives in this group include
Milk of Magnesia and Haley's M-O.
People who are dependent on laxatives need to slowly stop
using them. A doctor can assist in this process. In most people, this restores
the colon's natural ability to contract.
Treatment may be directed at a specific cause. For example,
the doctor may recommend discontinuing medication or performing surgery to
correct an anorectal problem such as rectal prolapse.
People with chronic constipation caused by anorectal dysfunction can use
biofeedback to retrain the muscles that control release of bowel movements.
Biofeedback involves using a sensor to monitor muscle activity that at the same
time can be displayed on a computer screen, allowing for an accurate assessment
of body functions. A health care professional uses this information to help the
patient learn how to use these muscles.
Surgical removal of the colon may be an option for people with severe symptoms
caused by colonic inertia. However, the benefits of this surgery must be weighed
against possible complications, which include abdominal pain and diarrhea.
Can constipation be serious?
Sometimes constipation can lead to complications. These
complications include hemorrhoids caused by straining to have a bowel movement
or anal fissures (tears in the skin around the anus) caused when hard stool
stretches the sphincter muscle. As a result, rectal bleeding may occur,
appearing as bright red streaks on the surface of the stool. Treatment for
hemorrhoids may include warm tub baths, ice packs, and application of a special
cream to the affected area. Treatment for anal fissure may include stretching
the sphincter muscle or surgical removal of tissue or skin in the affected area.
Sometimes straining causes a small amount of intestinal lining to push out from
the anal opening. This condition, known as rectal prolapse, may lead to
secretion of mucus from the anus. Usually eliminating the cause of the prolapse,
such as straining or coughing, is the only treatment necessary. Severe or
chronic prolapse requires surgery to strengthen and tighten the anal sphincter
muscle or to repair the prolapsed lining.
Constipation may also cause hard stool to pack the intestine and rectum so
tightly that the normal pushing action of the colon is not enough to expel the
stool. This condition, called fecal impaction, occurs most often in children and
older adults. An impaction can be softened with mineral oil taken by mouth and
by an enema. After softening the impaction, the doctor may break up and remove
part of the hardened stool by inserting one or two fingers into the anus.
Points to Remember
- Constipation affects almost everyone at one time or
- Many people think they are constipated when, in fact, their
bowel movements are regular.
- The most common causes of constipation are poor diet and
lack of exercise.
- Additional causes of constipation include medications,
irritable bowel syndrome, abuse of laxatives, and specific diseases.
- A medical history and physical examination may be the only
diagnostic tests needed before the doctor suggests treatment.
- In most cases, following these simple tips will help
relieve symptoms and prevent recurrence of constipation:
- Eat a well-balanced, high-fiber diet that includes beans,
bran, whole grains, fresh fruits, and vegetables.
- Drink plenty of liquids.
- Exercise regularly.
- Set aside time after breakfast or dinner for undisturbed
visits to the toilet.
- Do not ignore the urge to have a bowel movement.
- Understand that normal bowel habits vary.
- Whenever a significant or prolonged change in bowel habits
occurs, check with a doctor.
- Most people with mild constipation do not need laxatives.
However, doctors may recommend laxatives for a limited time for people with
Digestive Diseases Information Clearinghouse
2 Information Way
Bethesda, MD 20892–3570
Nutritional and Herbal Therapy for
- Eat more fresh vegetables, fruits, legumes and whole grains
(eg. beans, peas, broccoli, dark leafy salad greens).
- Fiber, especially insoluble fiber, is
extremely important in creating regular bowel movements and easy elimination.
Some sources include wheat bran, psyllium husks and ground flaxseeds.
- Increase water intake
- Decrease intake of refined foods (eg. white flour and
- Magnesium (500 mg a day) relaxes muscles and acts as
a mild laxative.
- Vitamin C (1,000 mg a day) in higher doses also has
mild laxative effects.
Tao of Nutrition
advises eating 5-10 figs on an empty stomach,
followed by a full glass of water. If you have no figs on hand, instead eat
two bananas on an empty stomach, followed by water. Another piece of advice is
to eat lightly steamed asparagus and cabbage before going to sleep at night.
High Performance is an excellent traditional Chinese formula that
improves digestive functioning and provides complex carbohydrates in the form
of wholesome grains, exotic seeds and herbs.
San Kuai Ding, a Chinese herbal formula, made with
aloe and rhubarb root, is very helpful for constipation.
Tao of Nutrition, by Maoshing Ni, Ph.D., C.A., and Cathy McNease,