Anal Fissures: Causes and Prevention

Medically Reviewed by Neha Pathak, MD on September 17, 2021
4 min read

An anal fissure is a cut or a tear in the thin, delicate lining of your anus.

The tear often exposes the muscle around the anus, called the anal sphincter. The damage can cause that muscle to spasm, which can pull apart the edges of the fissure even more. The spasms can cause pain and slow down the healing. Bowel movements can also keep the fissures from getting better.

An anal fissure is considered acute if it recently happened or if you've had it less than 6 weeks. It's considered chronic if it's been more than 6 weeks or it comes back often.

These tears are common, although you might think the pain and bleeding are symptoms of other conditions, like hemorrhoids. They can happen to both men and women. They can also happen to babies.

Adults between 20 and 40 are most likely to get them. But you can have them at any age, even though your risk generally goes down as you get older.

Anal fissures are seen more often with certain medical conditions, such as:

They're caused by trauma or injury that stretches your anal canal. Reasons for this can include:

Less often, having anal sex or putting things into your anus can overstretch the skin and cause a fissure.

Too much pressure, tight anal sphincter muscles, and poor blood supply to your anus may lead to their development and poor healing.

Anal fissures don't usually give way to more serious problems. They don’t cause cancer. But they can be very uncomfortable.

To help these fissures heal and keep them from coming back:

  • Eat a healthy diet that has plenty of fiber.
  • Stay well-hydrated.
  • Avoid being constipated.

Once you have an anal fissure, you'll definitely want to avoid getting another one, so follow these simple steps.

Get plenty of fiber. If you're constipated, passing large, hard, or dry stools can cause an anal fissure. Getting plenty of fiber in your diet -- especially from fruits and vegetables -- can help prevent constipation, though.

Get 20 to 35 grams of fiber per day. Foods that are good sources include:

  • Wheat bran
  • Oat bran
  • Whole grains, including brown rice, oatmeal, popcorn, and whole-grain pastas, cereals, and breads
  • Peas and beans
  • Seeds and nuts
  • Citrus fruits
  • Prunes and prune juice

If you can’t get enough fiber through your diet, try fiber supplements.

Whether you eat more fiber-rich foods or take supplements, boost your intake gradually until you notice softer, more-frequent bowel movements. Also, drink plenty of liquids as you take in more fiber. This will help you avoid bloating and gas.

Stay hydrated. That can help you prevent constipation. Drinking plenty of liquids adds fluid to your system, which can make stools softer and easier to pass. Be sure to drink more when the weather gets warmer or as you become more physically active.

Not all drinks are good choices for staying hydrated. Too much alcohol can dehydrate you. Also, although a caffeinated drink may help you go to the bathroom, too much caffeine can dehydrate you as well.

Exercise. One of the most common causes of constipation is a lack of physical activity. Exercise for at least 30 minutes most days to help keep your digestive system moving and in good shape. Work toward 150 minutes or more per week.

Don't ignore your urge to go. If your body tells you it's time to have a bowel movement, don't put it off till later. Waiting too long or too often can weaken the signals that let you know it's time to go. The longer you hold it in, the dryer and harder it can get, which makes it tougher to pass.

Practice healthy bowel habits. These tips can help lessen constipation and strain on the anal canal. Check these habits regularly to lower your risk of getting a painful anal fissure:

  • When using the bathroom, give yourself enough time to pass bowel movements comfortably. But don't sit on the toilet too long.
  • Don’t strain while passing stools.
  • Keep the anal area dry.
  • Gently clean yourself after each bowel movement.
  • Use soft, dye-free, and scent-free toilet paper or wipes.
  • Get treatment for ongoing diarrhea.

If you have other conditions that contribute to anal fissures -- like Crohn’s disease or IBS, for examples -- stay on top of your treatment.

Ask your doctor about laxatives. If adding fiber to your diet and taking fiber supplements aren't enough to treat constipation, laxatives may help. Some work in different ways.

Considered the safest kind of laxative, bulk-forming laxatives, or fiber supplements, increase your stools by allowing them to absorb and hold fluid. They also encourage contractions in the colon to move stools along. Bulk-forming laxatives include calcium polycarbophil, methylcellulose, psyllium, or wheat dextrin. You take them with water.

Other types of laxatives can help by:

  • Increasing the amount of water in the intestines
  • Lubricating stools so they can move more easily (mineral oil)
  • Drawing or pulling water into the colon
  • Stimulating the muscles in the intestines to speed up bowel movements

Ask your doctor which kind of laxative -- if any -- is right for you, and how long you should take it.

Frequent diaper changes for infants. Babies can get anal fissures, too. Change your baby's diaper often, and get medical help if they show any signs of constipation.

Show Sources


American Society of Colon & Rectal Surgeons: "Anal Fissure."

Cleveland Clinic: "Anal Fissures."

UpToDate: "Patient information: Anal fissure (Beyond the Basics)," "Patient information: High-fiber diet (Beyond the Basics)," "Patient information: Constipation in Adults (Beyond the Basics)." 

NHS Choices: "Anal fissure - Introduction," "Anal fissure - Prevention," "Laxatives - Introduction."

American Heart Association: "Whole Grains and Fiber."

Harvard School of Public Health, The Nutrition Source: "Fiber: Start Roughing It!"

National Digestive Disease Information Clearinghouse (NDDIC): "Constipation."

University of Michigan Health System: "Bowel Function Anatomy."

View privacy policy, copyright and trust info