by EBSCO Medical Review Board


An anal fissure is a cut or tear in the lining of the anus. The anus is the opening through which stool leaves the body.

Anal Fissure
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The exact cause is not known. In most people, it happens as a result of trauma to the anal lining. Trauma can be caused by:

  • A large, dry, or hard stool
  • Frequent diarrhea
  • Tightened anal sphincter, a group of muscles that open and close the anus
  • Childbirth
  • Receptive anal intercourse
  • Sexual abuse in children

Risk Factors

Things that may raise the risk of this problem are:

  • Constipation
  • Diarrhea
  • Pregnancy with vaginal delivery
  • Receptive anal intercourse
  • Sexual abuse in children
  • Colonoscopy
  • Dietary factors, such as a diet high in white bread and processed meat


The main problem is severe burning or tearing pain during and after a bowel movement. A person may also pass bright red blood or mucous.


The doctor will ask about your symptoms and health history. A physical exam will be done. It will focus on the anus. The doctor will likely be able to see an anal fissure. This is enough to make the diagnosis.

If the diagnosis is not clear, these tests may be done:

  • Digital rectal exam—to feel for any lumps or abnormalities
  • Anoscopy—to look at the anal canal with a scope
  • MRI scan or CT scan


The goal of treatment is to promote healing. Choices are:

  • Self care, such as warm sitz baths and increasing fiber and fluids
  • Medicines, such as:
    • Stool softeners or laxatives
    • Topical anesthetic to ease pain
    • Topical steroid cream to ease swelling
    • Topical nitrates and calcium channel blockers to increase blood flow and ease pain
    • Injected botulinum toxin to relax tightened muscles

People who are not helped by these methods may need surgery. Choices are:

  • Lateral internal sphincterotomy —Making a tiny incision in the sphincter muscle fibers to prevent spasms that result in straining during a bowel movement
  • Fissurectomy—Removing the fissure
  • Anal advancement flap—Covering the fissure with tissue from another part of the body
  • Anal dilation—Widening and stretching the anal canal (rare)


The risk of this problem may be lowered by eating a high fiber diet and drinking plenty of fluids.


American College of Gastroenterology 

American Society of Colon and Rectal Surgeons 


Canadian Association of Gastroenterology 

Canadian Society of Colon and Rectal Surgeons 


Anal fissure. EBSCO DynaMed website. Available at: Accessed March 16, 2021.

Anal fissure. American Society of Colon and Rectal Surgeons website. Available at: Accessed March 16, 2021.

Higuero T. Update on the management of anal fissure. J Visc Surg. 2015 Apr;152(2 Suppl):S37-43.

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