Rectal Bleeding and Inflammatory Bowel Disease

One of the many symptoms of inflammatory bowel disease (IBD) is bleeding. Blood might appear in or on the stool or some people may pass no stool at all at times, and just pass blood.

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Bleeding from the rectum and large intestine from IBD is typically red or bright red, while blood coming from higher up in the digestive tract could appear as darker or black stools. In most cases this bleeding is slow and steady.

However, you should get emergency attention if:

  • Bleeding is severe
  • You're vomiting blood
  • You faint or feel like you're going to

Blood in or on the stool can be frightening but it doesn't always mean that there's an emergency. It's sometimes part of an IBD flare-up and it should be discussed with a physician as soon as possible, especially if it hasn't happened in a while.

Bleeding means that there is some inflammation somewhere, and a change in treatment might be needed. Many treatments are available for IBD that can help stop the inflammation and the bleeding.

Bleeding in Ulcerative Colitis

Bleeding from the rectum is more common in ulcerative colitis than it is in Crohn's disease.

Ulcerative colitis often involves the rectum. Because the rectum is at the end of the large intestine, blood from this source is quite visible in or on the stool.

Bleeding also occurs with ulcerative colitis because this form of IBD attacks the lining of the large intestine. The ulcers that form in the mucosa of the large intestine tend to bleed.


What Causes Ulcerative Colitis?

In some cases, bleeding from ulcerative colitis can lead to significant blood loss. The ultimate goal of treatment will be to calm the inflammation and stop the bleeding, but treating the loss of blood may also be necessary.

In milder cases of anemia from ulcerative colitis, supplementing with iron, folic acid, and vitamin B12 may help to form new blood cells. In more serious cases of blood loss, a blood transfusion might be needed.

The most severe bleeding (called hemorrhaging) caused by ulcerative colitis could be life-threatening. This is not common, but if the bleeding can't be stopped, surgery to remove the colon and create an ileostomy may be needed.

During ileostomy surgery the large intestine is removed and a stoma is created to allow waste to pass outside the body and into a collection bag that is worn on the abdomen.

Another surgery might be done at a later date to create a j-pouch, which creates a way to go to the bathroom through the rectum instead of through the stoma.

Bleeding in Crohn's Disease

Crohn's disease causes blood in the stool less commonly than does ulcerative colitis, but this will vary between patients based on where the Crohn's is causing the inflammation.

Crohn's disease that is found in the colon or rectum, rather than in the small intestine, is more likely to cause blood to appear in or on the stool. Treating blood loss from Crohn's disease will be similar to that in ulcerative colitis:

  • Getting the IBD under control
  • Supplementing with vitamins
  • Blood transfusion, if necessary
  • Surgery, if necessary

With Crohn's disease, resection surgery may be done in order to remove the parts of the intestine that have been damaged by inflammation. J-pouch surgery isn't usually done for Crohn's disease because the Crohn's may reappear in the pouch.

Blood loss can also occur when an anal fissure has developed as a complication of Crohn's disease. Fissures are more common with Crohn's than they are with ulcerative colitis. In most cases, fissures can be treated successfully without surgery.

A Word From Verywell

Bleeding from the rectum and having blood in or on the stool is not uncommon in IBD. It's one of the hallmark signs of ulcerative colitis, because most patients do experience this sign.

Even so, bleeding should always be discussed with a gastroenterologist because it means that something is going on with the IBD and a change in therapy might be needed. Even if you've had bleeding before, it's important to talk it over with a doctor.

If you lose a lot of blood, you'll need immediate care. Additional symptoms such as fainting, dizziness, or severe pain could signal an emergency situation and calling an ambulance is the best course of action.

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  1. Ungaro R, Mehandru S, Allen PB, Peyrin-biroulet L, Colombel JF. Ulcerative colitis. Lancet. 2017;389(10080):1756-1770. doi:10.1016/S0140-6736(16)32126-2

  2. Gajendran M, Loganathan P, Catinella AP, Hashash JG. A comprehensive review and update on Crohn's disease. Dis Mon. 2018;64(2):20-57. doi:10.1016/j.disamonth.2017.07.001

Additional Reading
  • American Gastroenterological Association. "Inflammatory Bowel Disease." Apr 2008.

  • Crohns and Colitis Foundation of America. "What is Crohn’s Disease?." 2012. 

  • National Digestive Diseases Information Clearinghouse. "Crohn’s Disease." National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Dec 2011.