There are many possible causes of chronic constipation. But in most cases, no cause can be identified. Such constipation may be said to be "idiopathic" or "functional." That means there is a problem with the way the body is working.

Constipation can be made worse by one or more of the following:

  • poor general health,
  • inactivity,
  • use of certain medications,
  • laxative abuse,
  • depression or psychological distress,
  • low fiber diet, or
  • certain medical diseases.

Often, more than one factor contributes to the constipation. Here is a list of common examples.

Factors that may Cause Constipation

Functional/idiopathic Constipation with irritable bowel syndrome (IBS), idiopathic (unexplained) normal transit constipation, slow-transit constipation, pelvic floor dysfunction (obstructive)
Congenital (present at birth) Hirschsprung's disease
Structural Stricture, rectocele, intestinal pseudo-obstruction
Dietary Inadequate fiber intake, inadequate caloric intake
Environmental Compromised mobility, inadequate toileting facilities
(abnormality of the muscles)
Systemic sclerosis
Neurogenic (arising from
the nervous system)
Multiple sclerosis, Parkinson's disease, spinal cord injury
Endocrine/metabolic Diabetes mellitus, hyperparathyroidism, hypothyroidism, pregnancy, scleroderma
Pharmacologic (Medications) * Analgesics, anticholinergics, antidepressants, antihypertensives, antiparkinsonian agents, diuretics, possibly long-term laxative use, narcotics

* Common Medicines That May Cause Constipation

  • Antacids that contain aluminum (usually aluminum hydroxide)
  • Antidepressants
  • Antidiarrheal agents
  • Antiparkinson drugs
  • Antispasmodics
  • Diuretics ("water pills") that cause potassium loss
  • Iron supplements
  • Opiate-type pain medications
  • Medications to treat high blood pressure
    • Calcium channel blockers
    • Clonidine
  • Nasal decongestants and antihistamines
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)


You and Constipation

Animated Patient's Guide to Constipation