Causes of constipation

In most cases of chronic constipation, no specific cause is found. This is called chronic idiopathic constipation.

Lifestyle factors are predominantly the cause of constipation. These factors include:

  • Not eating enough fibre, such as fruit, vegetables and whole grains
  • Not drinking enough fluids, especially water
  • Lack of exercise
  • A change in your routine or lifestyle
  • Ignoring the urge to pass stools 
  • Stress 

Other causes


  • Constipation can be a side effect of certain medications. The list includes calcium and iron supplements, antacids (especially those containing aluminium), antidepressants, anti-epileptics, antipsychotics, opiate painkillers and diuretics.
  • Laxative overuse
  • Chronic lead poisoning

Endocrine and metabolic disorders

Neurological causes

  • Diabetes
  • Stroke
  • Multiple sclerosis 
  • Parkinson’s disease
  • Spinal cord damage or abnormalities (e.g. spina bifida and cerebral palsy)

Psychological causes

  • Anxiety or depression
  • Eating disorders
  • Psychiatric problems, such as those brought on by sexual abuse, violence or trauma

GI disorders

  • Irritable bowel syndrome (IBS)
  • Anal fissure
  • Inflammatory bowel diseases (Crohn’s or ulcerative colitis) or diverticulitis 
  • Colon cancer
  • Hirschsprung's disease (a birth defect in which some nerve cells are absent in the large intestine)
  • Ano-rectal malformation

Causes of constipation in babies and children

  • In infants, bottle-fed babies are more likely to suffer from constipation. In children, poor diet, fear of using the toilet and problems toilet training can all lead to constipation.

Causes of dyssynergic constipation

Dyssynergic constipation occurs if there’s an inability to coordinate abdominal, recto-anal and pelvic-floor muscles to allow for defecation. This failure of recto-anal coordination may be because of impaired rectal contraction, paradoxical anal contraction or inadequate anal relaxation.

Causes of low transit constipation

With slow transit constipation there is decreased colonic motility and frequency of bowel movement, and they occur only periodically. People with this type of constipation have a blunted response to waking, meals, fibre or laxatives.

Physicians at the Mayo Clinic did a study looking at the number and distribution of pacemaker cells, and found an absence or decreased number of these cells and enteric neurons in these patients.

Read more:
Risk factors of constipation

Reviewed by Kim Hofmann, registered dietitian, BSc Medical (Honours) Nutrition and Dietetics, BSc (Honours) Psychology, December 2017.

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