A rectal ulcer happens when one or more of the mucus layers that line the rectum are injured or damaged, resulting in a painful sore.

Your rectum is the last few inches of your large intestine (colon) before it ends at your anus.

The rectum helps store stool until you’re ready to pass it out of your body. When you have an ulcer, the normal processes of digestion and passing waste can be painful and result in further damage to the ulcer.

Read on to learn more about how to recognize the symptoms and causes of a rectal ulcer, as well as how doctors diagnose and treat rectal ulcers.

The most common signs and symptoms of an ulcer in your rectum include:

The exact cause of a rectal ulcer isn’t always clear.

But some of the more common causes of rectal ulcers can include:

In rare cases, rectal ulcers can also develop without an obvious cause if you have a condition called solitary rectal ulcer syndrome (SRUS). SRUS often means you’ll have rectal ulcers without any other symptoms like pain or changes in your stool.

The most common risk factors for rectal ulcers include:

Untreated rectal ulcers can result in long-term bleeding that can result in anemia.

Rectal ulcer bleeding can also cause a condition called acute hemorrhagic rectal ulcer syndrome (AHRUS). This condition is more common in people with diabetes or who take blood thinners. If it’s untreated, AHRUS can be deadly.

A medical professional will usually ask for a medical history and do a physical exam to check your overall health. This may include a digital rectal exam (DRE) to check for signs of injury or disease.

Imaging tests are often needed to look more closely at the rectum to confirm a diagnosis, including:

A sigmoidoscopy or colonoscopy may be needed to look further inside your rectum and colon. These tests are done by inserting a thin tube with a light and camera into your rectum to get real-time, detailed images of your rectum.

A medical professional may also take a tissue sample (biopsy) from your ulcer to test it for infections or cancer.

  • severe abdominal pain
  • severe pain during a bowel movement
  • long-term constipation or diarrhea
  • nausea
  • vomiting
  • not being able to eat or drink
  • loss of consciousness

Many rectal ulcers go away without medical treatment when you make diet or lifestyle changes.

Here are some common medical treatments for rectal ulcers:

  • laxatives to reduce how much you have to strain on the toilet
  • stool softeners to reduce the chance of hard stools damaging your rectum
  • topical medications like hydrocortisone to reduce swelling and relieve pain
  • antibiotics for bacterial infections, especially if they’re caused by an STI

Rectal ulcer surgery

You may require surgery if you have a rectal ulcer that is caused by injury or rectal prolapse.

Severe bleeding ulcers are treated with an endoscopic surgery that involves inserting a camera and surgical tools into the rectum to remove them manually.

The treatment for rectal prolapse is rectopexy. This surgery is done by inserting surgical tools into your abdomen to pull the rectum back up into place. Depending on how severe your prolapse is, the procedure can be done with only a few small incisions (laparoscopic surgery) or by opening the skin above the rectum (open surgery).

A high fiber diet can help if you have a rectal ulcer.

Here are some high fiber foods you can try to eat if you have a rectal ulcer — and some foods you may want to avoid.

Eat

  • fruits
  • vegetables
  • whole grains, such as oats
  • High fiber legumes like lentils
  • water with electrolytes
  • moderate amounts of caffeine

Don’t eat

  • red meats like beef
  • dairy products like milk and cheese
  • High fat foods like butter
  • processed, greasy foods
  • foods high in sugar
  • alcohol

If it’s treated, a rectal ulcer can heal in about 2–4 weeks. A rectal ulcer where a rectal biopsy is performed heals in about 4 weeks.

Untreated rectal ulcers that become severe may last for weeks or months until they’re treated, especially if they result from another condition like IBD.

Rectal ulcers are usually preventable if they’re due to diet or daily routine.

Here are some prevention tips for rectal ulcers:

  • drink water to keep your stool moist and easy to pass
  • eat high fiber foods to normalize bowel movements
  • get up and walk around at least once an hour if you sit for long periods
  • don’t strain or push when on the toilet
  • wipe yourself gently after bowel movements
  • be gentle and use lubrication when you insert anything into your anus, such as an enema

Rectal ulcers happen when your rectum is injured or damaged.

Many rectal ulcers go away on their own, but untreated rectal ulcers can be extremely painful and make it difficult to pass stool.

Contact a medical professional if you’re experiencing severe pain around your rectum.