Skip to Content

Symptom Checker

Step 4: Read and complete the decision guide to learn more about your symptoms.

Rectal Bleeding

Your bleeding may be a medical emergency. You may require intravenous fluids, a blood transfusion, or an urgent treatment to stop your bleeding or prevent it from restarting. Even if your bleeding has stopped, you should visit your doctor or an emergency facility today.

Avoid taking aspirin or non-steroidal pain medications (ibuprofen (Motrin), naproxyn (Naprosyn, Aleve) and others) before you see a doctor, since these medicines may worsen your bleeding.

Common causes of large bleeds include:


Up to one half of all lower intestinal hemorrhages in adults results from bleedingĀ "diverticuli." Many adults form "diverticuli," which are small, balloon-like pouches that push out from the colon lining. Most diverticuli form next to a small artery, since the intestine tissue is weakest around these small arteries. (The muscle of the intestine has a gap where each artery is located and this gap is the easiest place for a bulge to push through.) As a diverticuli expands, this small artery can be torn and cause brisk bleeding.

Fragile (and abnormally formed) blood vessels

Some lower intestinal bleeding episodes in adults are caused by abnormal blood vessels near the inner surface of the intestine. This type of blood vessel, known as an "arteriovenous malformation" (AVM, also called "angiodysplasia") forms in older adults and may be present in multiple locations. When damaged or broken, they may bleed heavily.

Peptic ulcer

It is possible for peptic ulcers to bleed heavily. Frequently this results in black, tar-like blood from the rectum. It occasionally causes maroon or red blood from the rectum.

Colon polyps

Colon polyps are bulges of intestine tissue that dangle or protrude into the hollow of the colon. They often bleed. Polyps need to be removed because they may form cancers if they are left in the intestine.

Colorectal cancer

Cancer usually does not cause a large, sudden bleed, but it can occasionally cause this symptom. Colorectal cancer is the second most common cause of death from cancer in the United States. It is preventable, if colon polyps are discovered and removed. Colorectal cancer can be cured by surgery if it is found at an early stage.


Please provide feedback to help us improve the Symptom Checker.

Related Documents

Disclaimer: This content should not be considered complete and should not be used in place of a call or visit to a health professional. Use of this content is subject to specific Terms of Use & Medical Disclaimers.