Causes of Constipation

Constipation can have a variety of simple causes such as an inactive lifestyle, poor diet, dehydration or fecal impaction. Life-threatening causes can occasionally occur such as bowel obstruction or colon cancer. See your doctor promptly for a full diagnosis.

Simple Causes: A variety of simple ailments can cause constipation, such as:

Concerning Causes: Although not necessarily the most common causes, some of the causes that the doctor may be most concerned about include:

Anal or Rectal Causes: Various disorders of the anus or rectum can cause constipation, either through physical problems, or from the person’s avoidance of anal or rectal pain. Some examples include:

Read more about: Rectal Pain.

Digestive System Causes: A number of gastrointestinal disorders, some of them serious and life-threatening disorders, are possible causes of constipation that can occur, such as:

Nerve Disorders: Damage to the nerves of the bowel or rectal region can cause constipation. Some examples include:

Metabolic and Endocrine Disorders: Various disorders of the body’s chemical balance (especially in relation to water balance), metabolism or endocrine systems can cause constipation. Some examples include:

Other Causes: A number of other issues can cause constipation. Some examples include:

Similar Symptoms: See also causes of similar symptoms to constipation, such as:

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Back to: « Constipation

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What causes constipation?

Constipation can happen for many reasons, and constipation may have more than one cause at a time. Among the most common causes of constipation are

Constipation may become worse because of the following factors:

Diets low in fiber

Fiber helps stool stay soft. Drink liquids to help fiber keep stool soft.

Older adults commonly have constipation because of limited dietary fiber, lack of physical activity, and medications.

Lack of physical activity

If you don’t exercise or move around regularly you may get constipated. For example, people may be less active because they

  • have other health problems
  • sit all day and don’t exercise regularly
  • have to stay in bed most of the time because of an illness or accident


Some medicines that doctors prescribe to treat other health problems can cause constipation. Medicines that can cause constipation include

Life changes or daily routine changes

Constipation can happen when your life or daily routine changes. For example, your bowel movements can change

  • when you travel
  • if you become pregnant
  • as you get older

Ignoring the urge to have a bowel movement

If you ignore the urge to have a bowel movement, over time, you may stop feeling the need to have one. You may delay having a bowel movement because you do not want to use toilets outside of your home, do not have access to a toilet, or may feel you are too busy. This habit can lead to constipation.

Certain health problems

Some health problems can make stool move more slowly through your colon, rectum, or anus, causing constipation. These health problems include

Gastrointestinal (GI) tract problems

Problems in your GI tract that compress or narrow your colon and rectum can cause constipation. These problems include

Functional GI disorders

Functional GI disorders happen when your GI tract behaves in an abnormal way, yet without evidence of damage due to a disease. For example, IBS is a common functional GI disorder, and many people with IBS can have IBS with constipation.

Source: NIDDK (NIH)1

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People can have constipation—trouble having a bowel movement—when they:

  • Change what they eat
  • Take certain medicines, including Namenda®
  • Get less exercise than usual
  • Drink less fluid than usual

Source: NIA (NIH)2

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What Causes Constipation?

Doctors do not always know what causes constipation. It may be a poor diet, not getting enough exercise, or using laxatives too often. Reasons for constipation include:

  • Diet. You may become constipated if you don’t eat enough high-fiber foods like vegetables, fruits, and whole grains. Also, eating a lot of high-fat meats, dairy products and eggs, or rich desserts and sugary sweets may cause constipation. People who live alone may lose interest in cooking and eating. As a result, they start using prepared foods. These foods tend to be low in fiber and may lead to constipation. Also, people who have problems with their teeth tend to choose soft, processed foods that contain little fiber.

Many older people don’t drink enough water and other fluids. This often is the case when they’re not eating regular meals. Water and other liquids may help people stay regular.

Source: NIA (NIH)3

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If you or a family member has constipation, it can be caused by a number of factors, most common of which include not getting enough fluid or fibre in your diet.

Constipation may also be a symptom of a more serious problem, like bowel cancer.

Source: New Zealand Health4

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Causes of constipation

Eating plenty of vegetables and fruit will generally give you enough fibre to have regular, easy bowel motions.

However, if you eat a lot of meat, or processed or refined foods, there might not be enough fibre in your bowel. The waste will move slowly, causing constipation and wind.

Also, if you don’t drink enough and get dehydrated, your bowel will absorb more fluid which will dry out the food waste - making your motions harder and difficult to pass.

As well as diet, constipation can be caused by:

  • waiting too long to go to the toilet
  • not getting enough physical activity
  • travel or other change in routine
  • prolonged periods of immobility
  • taking certain medicines - especially some pain-killers or using laxatives for too long
  • pregnancy
  • depression
  • hormonal problems such as an underactive thyroid gland
  • an underlying problem of your nerves or bowel.

Source: New Zealand Health5

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What causes constipation

Constipation in adults has many possible causes. Sometimes there is no obvious reason.

The most common causes include:

  • not eating enough fibre - such as fruit, vegetables and cereals
  • not drinking enough fluids
  • not exercising or being less active
  • often ignoring the urge to go to the toilet
  • changing your diet or daily routine
  • stress, anxiety or depression
  • a side effect of medication

Constipation is also common during pregnancy and for 6 weeks after giving birth.

In much rarer cases, constipation may be caused by a medical condition.

Source: NHS Choices UK6

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Babies and toddlers: what causes constipation

Constipation in babies and toddlers has many possible causes. Sometimes there is no obvious reason.

It usually happens when your child:

  • first starts taking formula or processed foods as a baby
  • is being potty trained as a toddler
  • has just started school

The most common causes include:

  • not eating enough fibre - such as fruit, vegetables and cereals
  • not drinking enough fluids
  • overfeeding - including giving babies too much milk
  • fear or anxiety about using the toilet - at home or at school
  • poor potty training - such as feeling pressured or being regularly interrupted

In much rarer cases, constipation in babies and toddlers may be caused by a medical condition.

Source: NHS Choices UK7

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Hirschsprung disease: Many healthy infants and children have difficulty passing stool or infrequent bowel movements. However, unlike healthy children and infants, kids with Hirschsprung disease typically do not respond to constipation medicines given by mouth.

Source: NIDDK (NIH)8

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Colon cancer: Its first symptoms may be a change in bowel habits - either diarrhoea or constipation, sometimes with blood or mucus (slime).

Source: New Zealand Health9

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Multiple sclerosis: Many people with MS also have problems with their bowel function.

Constipation is the most common problem. You may find passing stools difficult and pass them much less frequently than normal.

Source: NHS Choices UK10

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Some causes may include:11 Causes of Constipation:

Causes List for Constipation

List of possible causes of Constipation or similar symptoms may include:12

... Full Causes List for Constipation »

Risk Factors for Constipation

Who is more likely to become constipated?

Constipation is common among all ages and populations in the United States, yet certain people are more likely to become constipated, including

Source: NIDDK (NIH)13

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There are a number of factors which may contribute to the development of constipation. These include:

Source: Queensland Health14

Specific Risk Factors for Constipation

Down Syndrome: In some cases, the weak muscles can cause problems along the digestive tract, leading to various digestive problems, from difficulty swallowing to constipation. Families may need to work with a gastroenterologist to overcome these problems.

Source: NICHD (NIH)15

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  1. Source: NIDDK (NIH): health-information/ digestive-diseases/ constipation/ all-content
  2. Source: NIA (NIH): health/ alzheimers-disease-common-medical-problems
  3. Source: NIA (NIH): health/ concerned-about-constipation
  4. Source: New Zealand Health: your-health/ conditions-and-treatments/ diseases-and-illnesses/ constipation
  5. ibid.
  6. Source: NHS Choices UK: conditions/ Constipation/ 
  7. ibid.
  8. Source: NIDDK (NIH): health-information/ digestive-diseases/ hirschsprung-disease
  9. Source: New Zealand Health: your-health/ conditions-and-treatments/ diseases-and-illnesses/ constipation
  10. Source: NHS Choices UK: conditions/ multiple-sclerosis/ symptoms/ 
  11. Source: Human Phenotype Ontology
  12. Source: Algorithmically Generated List
  13. Source: NIDDK (NIH): health-information/ digestive-diseases/ constipation/ all-content
  14. Source: Queensland Health: HealthCondition/ condition/ 9/ 46/ 31/ constipation
  15. Source: NICHD (NIH): health/ topics/ down/ conditioninfo/ Pages/ associated.aspx

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.