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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. In addition, 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 causes,
prevention, and treatment will help most people find relief.
According to the 1991 National Health Interview Survey, about 4
1/2 million people in the United States say they are constipated
most or all of the time. Those reporting constipation most often
are women, children, and adults age 65 and over. Pregnant women
also complain of constipation, and it is a common problem
following childbirth or surgery.
Constipation is the most common gastrointestinal complaint in
the United States, resulting in about 2 million annual visits to
the doctor. However, most people treat themselves without seeking
medical help, as is evident from the $725 million Americans spend
on laxatives each year.
To understand constipation, it helps to know how the colon
(large intestine) works. As food moves through it, the colon
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. (See figure 1.)
The hard and dry stools of constipation occur when the colon
absorbs too much water. This happens because the colon's muscle
contractions are slow or sluggish, causing the stool to move
through the colon too slowly. Figure 2 lists the most common
causes of constipation.
Common Causes of Constipation
- Not enough fiber in diet
- Not enough liquids
- Lack of exercise
- Irritable bowel syndrome
- Changes in life or routine such as
pregnancy, older age, and travel
- Abuse of laxatives
- Ignoring the urge to have a bowel movement
- Specific diseases such as multiple sclerosis
- Problems with the colon and rectum
- Problems with intestinal function (Chronic
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 become constipated.
Fiber--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 almost unchanged through
the intestines. The bulk and soft texture of fiber help prevent
hard, dry stools that are difficult to pass.
On average, Americans eat about 5 to 20 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 in which the natural fiber is removed.
A low-fiber diet also plays a key role in constipation among
older adults. They often lack interest in eating and may choose
fast foods low in fiber. In addition, loss of teeth may force
older people to eat soft foods that are processed and low in
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. Other liquids,
like coffee and soft drinks, that contain caffeine seem to have a
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
Pain medications (especially narcotics), antacids that contain
aluminum, antispasmodics, antidepressants, iron supplements,
diuretics, and anticonvulsants for epilepsy can slow passage of
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 older adults who are preoccupied with having
a daily bowel movement.
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. Figure 3 lists the
diseases that cause constipation.
Diseases That Cause Constipation
Neurological disorders that may cause constipation
Metabolic and endocrine conditions include:
- Multiple sclerosis
- Parkinson's disease
- Chronic idiopathic intestinal
- Spinal cord injuries.
Systemic disorders include:
- 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
Problems with Intestinal Function (Chronic Idiopathic
Also known as functional constipation, chronic idiopathic (of
unknown origin) constipation is rare. However, some people are
chronically constipated and do not respond to standard treatment.
This chronic constipation may be related to multiple 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 left or lower (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
Most people 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 depends on the duration and severity of the
constipation, the person's age, and whether there is blood in
stools, recent changes in bowel movements, or weight loss.
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). Recording
eating habits, medication, and level of physical activity or
exercise also helps the doctor determine the cause of
A physical exam may include a digital 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
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.
Because of an increased risk of colorectal cancer in older adults,
the doctor may use these tests to rule out a diagnosis of cancer:
- Barium enema x-ray
- Sigmoidoscopy or colonoscopy
- Colorectal transit study
- Anorectal function tests.
Barium Enema X-Ray
A barium enema x-ray 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 8 ounces of a special liquid every 15 minutes for about 4
hours. This liquid flushes 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 inaccurate exam.
Because the colon does not show up well on an x-ray, the doctor
fills the organs with a barium enema, a chalky liquid to make the
area visible. Once the mixture coats the organs, 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 colon (sigmoid) is called a
sigmoidoscopy. An examination of the rectum and entire colon is
called a colonoscopy.
The night before a sigmoidoscopy, the patient usually has a
liquid dinner and takes an enema in the early morning. A light
breakfast and a cleansing enema an hour before the test may also
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 organs 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.
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, which are visible on 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. A catheter or air-filled
balloon inserted into the anus is slowly pulled back through the
sphincter muscle to measure muscle tone and contractions.
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 and expels the solution. The doctor studies
the x-rays for anorectal problems that occurred while the patient
emptied the paste.
Although treatment depends on the cause, severity, and
duration, in most cases dietary and lifestyle changes will help
relieve symptoms and help prevent constipation.
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 soup, engaging in daily exercise, and
reserving enough time to have a bowel movement. In addition, the
urge to have a bowel movement should not be ignored.
Most people who are mildly constipated do not need laxatives.
However, for those who have made 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
People who are dependent on laxatives need to slowly stop using
the medications. A doctor can assist in this process. In most
people, this restores the colon's natural ability to contract.
- 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®,
- Stimulants cause rhythmic muscle contractions in the
intestines. Brand names include Correctol®,
Feen-A-Mint®, 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®,
Dialose®, and Surfak®.
- Lubricants grease the stool enabling it to move through the
intestine more easily. Mineral oil is the most common
- 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®,
Citrate of Magnesia®, and
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.
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 that appears as bright red
streaks on the surface of the stool. Treatment for hemorrhoids may
include warm tub baths, ice packs, and application of a 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 is known as
rectal prolapse and 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 an
enema. After softening the impaction, the doctor may break up and
remove part of the hardened stool by inserting one or two fingers
in the anus.
Constipation affects almost everyone at one
time or another.
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
A medical history and physical examination may
be the only diagnostic tests needed before the doctor suggests
In most cases, following these simple tips
will help relieve symptoms and prevent recurrence of
Eat a well-balanced, high-fiber diet that
includes beans, bran, whole grains, fresh fruits, and
Drink plenty of liquids.
Set aside time after breakfast or dinner
for undisturbed visits to the toilet.
Do not ignore the urge to have a bowel
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 chronic constipation.