Intended for healthcare professionals

Practice Therapeutics

Laxatives for chronic constipation in adults

BMJ 2012; 345 doi: (Published 01 October 2012) Cite this as: BMJ 2012;345:e6168
  1. Alexander C Ford, senior lecturer, honorary consultant gastroenterologist12,
  2. Nicholas J Talley, professor of medicine3
  1. 1Leeds Gastroenterology Institute, St James’s University Hospital, Leeds LS9 7TF, UK
  2. 2Leeds Institute of Molecular Medicine, Leeds University, Leeds LS2 9JT
  3. 3Faculty of Health, University of Newcastle, Callaghan, NSW2308, Australia
  1. Correspondence to: A C Ford alexf12399{at}

A 25 year old woman attends her general practitioner with a six month history of constipation. Despite having increased her daily intake of fibre and water, she is still only passing two stools a week. Her general practitioner excludes red flag features (box) and finds no abnormality on examination, apart from a loaded rectum. He suggests she try using laxatives to increase her stool frequency, but she is reluctant as she has heard they are not very effective and can have adverse effects.

Red flag features in chronic constipation12

  • Recent onset of constipation in older age (> 50 years)

  • Obstructive symptoms

  • Rectal bleeding

  • Weight loss

  • Family history of colon cancer

  • Iron deficiency anaemia

  • Haem positive stool

What are laxatives?

Laxatives are foods or drugs that, when ingested, act directly on the gut (or gut contents) to increase stool frequency or ease stool passage. They differ from motility agents such as prucalopride, which exert a promotility effect after systemic absorption. Laxatives are used to treat chronic constipation, usually defined as the presence of difficult or infrequent passage of stool, often accompanied by straining or a sensation of incomplete evacuation, with symptoms present for more than three months.

Chronic constipation is common in the general population. A recent meta-analysis of population based observational studies reported a pooled prevalence of 14% worldwide, with a significantly higher prevalence in women and people of lower socioeconomic status.3 However, symptoms often fluctuate, and recent community data suggest that persistent symptoms over 10 to 20 years affect only 3% of the population.4 Population based studies also show that constipation affects quality of life, is associated with several comorbidities (including haemorrhoids and anal fissure),5 and may be associated with a modest reduction in survival.6

Laxatives may act by several mechanisms, including bulking the stool volume, softening the stool consistency, increasing the stool volume …

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