Constipation is a common problem regardless of sex, age or race. It is defined as infrequent, difficult or incomplete bowel movements. Normal bowel movement frequency may range from three bowel movements per day to three bowel movements per week. Constipation is therefore defined by most authorities as less than three bowel movements a week. However, constipation may have other defining features. These include:

  • The passage of hard, pellet-like stools
  • A decrease in one’s typical bowel movement frequency (not necessarily less than three bowel movement’s a week)
  • The need to strain when having a bowel movement
  • A sense of incomplete evacuation of the rectum with a bowel movement
  • The need to use enemas, suppositories, oral laxatives or manual maneuvers such as digital stimulation or pelvic floor support to maintain regularity of bowel movements

What are the causes?

There are many reasons for the development of constipation. These include dietary and lifestyle habits, medications and behavioral issues. For some constipation may be a symptom associated with a medical condition including a number of structural, metabolic, myopathic, neuropathic or functional disorders. For many there may be more than one underlying cause for their constipation.

Common causes of constipation:

  • Inadequate fiber in the diet
  • Inadequate hydration (dehydration)
  • Lack of physical activity (especially in elderly)
  • Medications
  • Changes in life or routine such as pregnancy, aging, and travel
  • Ignoring the urge to have a bowel movement
  • Irritable bowel syndrome
  • Mechanical obstruction of the colon and/or rectum
  • Systemic diseases and other medical conditions

Lack of adequate dietary fiber

People who eat a high-fiber diet are less likely to become constipated. A diet low in fiber or a diet high in fats is commonly associated with constipation. 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 may be difficult to pass.

Americans eat an average of 5 to 14 grams of fiber daily [1], which is short of the 25 to 35 grams recommended by the American Dietetic Association. Both children and adults often 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 foods that are quick to make or buy. These fast foods or prepared foods, both are typically low in fiber and high in fat. Also, difficulties with chewing or swallowing may cause older people to eat soft foods that are processed and consequently low in fiber.

[1] 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.

Adequate hydration

Research has not yet demonstrated that a low fluid intake causes constipation or that an increase in orally ingested fluids alone effectively treats constipation. Nonetheless, many individuals report relief of their constipation with an increase intake of oral fluids. Orally ingested liquids are believed to add fluid to the colon and bulk to stools, making bowel movements softer and easier to pass. However caution must be exercised as beverages containing caffeine, such as coffee and soft drinks, are likely to worsen one’s symptoms by promoting dehydration. Alcohol is another beverage that causes dehydration and may worsen constipation in the long run. It is important to drink fluids that hydrate the body, especially in the heat or when consuming large quantities of caffeine-containing or alcoholic beverages.

Lack of physical activity

A lack of physical activity can lead to constipation. For example, constipation often occurs after an accident or during an illness when one must stay in bed and cannot exercise. Lack of physical activity is thought to be one of the reasons constipation is more common in older people. Moreover, increased physical activity is more likely to stimulate bowel motility and improve the symptoms of constipation.


Many medications can cause constipation, including prescription and nonprescription drugs. The list below includes commonly prescribed drugs and common over-the-counter drugs that may promote constipation. Be aware that there are many other drugs not listed below that may cause constipation. If you notice the development of constipation with the use of a medication, this should be brought to the attention of your physician.

Prescriptions drugs

  • Pain medications, particularly those containing opiates
  • Muscle relaxants
  • Antispasmodics
  • Antidepressants
  • Antiparkinson drugs
  • Blood pressure medications (beta blockers and calcium channel blockers)
  • Diuretics
  • Anticonvulsants
  • Antipsychotic drugs
  • Antihistamines

Nonprescription drugs

  • Antacids that contain aluminum and calcium
  • Iron supplements
  • Antihistamines
  • Antidiarrheal agents
  • Calcium supplements
  • Nonsteroidal anti-inflammatory agents

Changes in life or routine

During pregnancy, women may be constipated because of hormonal changes or because the uterus compresses the intestine. Aging may also affect bowel regularity possibly due to slowing metabolism, decreased intestinal motor activity or decreased muscle tone and strength. Finally, people may become constipated when traveling, because their normal diet and daily routine are disrupted.

Ignoring the urge to have a bowel movement

People who ignore the urge to have a bowel movement may eventually stop feeling the need to have one, which can lead to constipation. Some people delay having a bowel movement because they do not find it convenient to use toilets outside the home. Others ignore the urge because of emotional stress or because they are simply too busy. Children may postpone having a bowel movement because of stressful toilet training or because they do not want to interrupt their play.

Irritable bowel syndrome (IBS)

IBS is a common chronic disorder causing alteration in one’s bowel habits as well as abdominal discomfort, although pain is usually relieved with bowel movement. Bowel habit alterations can include constipation, diarrhea, and a mixed pattern in which the bowels alternate between that of diarrhea and constipation. IBS is believed to occur due to disruption in the proper function of the bowels. This may include alterations in normal bowel motility, bowel secretion or bowel pain sensation. IBS is therefore referred to as a functional bowel disorder. There are specific therapies for IBS that may also help the associated symptom of constipation.

Mechanical obstruction of the colon or rectum

There are a number of disorders that may compress, squeeze or narrow the intestines. This may result in a physical barrier to the easy passage of the stool through the bowels. Such conditions may present with constipation.

Causes of mechanical obstruction

  • Colon cancer
  • Strictures of the colon, rectum or anus
  • Adhesions (scar tissue from prior surgery)
  • Diverticulosis
  • External compression of the colon
  • Rectocele
  • Megacolon (Hirschsprung’s disease)
  • Anal fissure
  • Rectal outlet obstruction due to pelvic floor dyssynergia or anismus (abnormal muscle contraction and relaxation impairing the ability to expel stool from the rectum)

Systemic diseases and conditions

A number of systemic diseases and conditions may also cause constipation. These include neurologic disorders, myopathies, metabolic and endocrine disorders. These disorders can slow the movement of stool through the colon, rectum, or anus.

Conditions that can cause constipation:

  • Neurological disorders
    • Multiple sclerosis
    • Parkinson's disease
    • Stroke (cerebral vascular disease)
    • Spinal cord injury or tumor
  • Myopathies
    • Amyloidosis
    • Scleroderma
  • Metabolic and endocrine conditions
    • Diabetes Mellitus
    • Hypothyroidism (under active thyroid)
    • Uremia (kidney failure)
    • Hypercalcemia (high calcium level in blood
    • Hypokalemia (low potassium level in blood)
    • Hypomagnesemia (low magnesium level in blood)
    • Heavy metal poisoning
  • Other conditions
    • Depression
    • History of physical or sexual abuse

What to do about constipation?

You should see your primary care provider if the above-mentioned lifestyle, dietary or behavioral changes do not relieve the constipation.

You should see a physician right away if there are associated symptoms of blood in the stool, rectal bleeding, abdominal pain, painful bowel movements, unexplained weight loss, associated nausea or vomiting or constipation lasting more than three weeks.

If you are 50 or older, you should have a routine colonoscopy. Your physician may pursue additional testing such as lab work, radiographic studies of the bowels or manometric studies of the bowels or rectum.
Remember, constipation is common, may have one or more causes and is treatable.

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