An anal fissure is a shallow ulceration or tear in the tissue along the anal canal. During bowel movements, irritation of the fissure can trigger a spasm in the anal sphincter, the muscle that surrounds the opening of the anus. Such spasms are often quite painful and may be accompanied by bleeding. This condition is more common among women.

What Causes Anal Fissures?

  • Anal fissures are typically caused when large, hard stools tear the lining of the anal canal as they pass.
  • Trauma to the inner lining of the anus can cause a fissure.
  • Fissures may also occur as a secondary complication to anal surgery, proctitis (inflammation of the rectum) or other disorders.
  • The risk of anal fissures increases with constipation, multiple pregnancies, and repeated use of enema nozzles. Also, older people may be more likely to develop anal fissures, owing to age-related changes in the skin as well as increased frequency of constipation. Obesity may lead to increased sweating, which may be an aggravating factor.
  • Underlying medical conditions such as Crohn’s disease and ulcerative colitis, anal cancer, leukemia; infectious diseases (e.g., tuberculosis), and sexually transmitted diseases (e.g., gonorrhea, chancroid, syphilis, chlamydia and HIV) can cause anal fissure.
  • Tight or spastic anal sphincter muscles (muscles that control the closing of the anus), chronic poor bowel habits, anorectal scarring and decreased blood flow to the rectum or anus also can cause fissures.

Symptoms of Anal Fissures

  • Sharp or burning rectal pain during and immediately after bowel movements, especially when the stool is hard or bulky
  • Diarrhea or constipation
  • Bright red blood in stool or bloody streaks on toilet paper or underwear
  • Rectal itching
  • A visible crack or tear or inflammation in the anus or anal canal
  • Urinary problems, such as painful or frequent urination or inability to urinate
  • Foul-smelling discharge


  • Eat a high-fiber diet that includes lots of fresh fruits and legumes and whole-grain products.
  • Maintain good hygiene in the anal area. Use talcum powder or corn starch to keep the area dry.
  • Drink plenty of liquids (at least eight glasses of water a day) to soften the stool and help prevent constipation.
  • Don’t strain during bowel movements. Promptly treat all occurrences of constipation and diarrhea.
  • Lubricate the anorectal area using petroleum jelly. Avoid irritating the area.
  • Avoid constipating foods and ask your doctor whether any drugs you take may be the cause of constipation.
  • Soak in a warm bath for 10-20 minutes several times each day to promote relaxation of anal muscles.

Diagnosis of Anal Fissures

  • Patient history and physical examination are needed.
  • Examination with an anoscope or sigmoidoscope are required to detect the fissure and to rule out other causes of rectal bleeding.
  • The doctor will perform visual inspection of the anus or gently examine the anus with the tip of the finger.

How to Treat Anal Fissures

  • Most anal fissures heal naturally within a few days (although spasms of the sphincter may aggravate the condition and delay healing).
  • A warm sitz bath after a difficult bowel movement may ease painful spasms of the anal sphincter. Apply a nonprescription topical cream, such as zinc oxide or a hemorrhoidal preparation, after the bath.
  • Stool softeners may be advised; check with your doctor.
  • Nitroglycerin ointment (0.2%) may be prescribed to relieve spasms and promote healing.
  • Local injections of botox (botulinum toxin) are very effective for treating chronic anal fissures.
  • Persistent or recurrent anal fissures may require surgical removal of the fissure or anal dilatation to relieve spasms and relax the anus. Although postoperative healing is usually rapid and complete, fissures may recur.

When to Call a Doctor

  • If symptoms of an anal fissure persist, contact your doctor.
  • Blood in the stool can be a warning sign of a more serious condition and should be evaluated by your doctor.


Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference

Simeon Margolis, M.D., Ph.D., Medical Editor

Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at

Published: 23 Aug 2011

Last Modified: 08 Sep 2015