When to worry about blood in your stool (rectal bleeding)

Poop may be the favorite topic of preschoolers, yet very few adults want to talk about it. And if a problem shows up, like blood in your stool, it can double the embarrassment.

But blood in your stool can be a sign that something needs attention in your body, so it’s worth a conversation with your doctor.

“The thing that everyone worries the most about is cancer, but blood in your stool can be caused by a whole variety of things,” says gastroenterologist David Richards, M.D.

Blood in your stool can be caused by many different issues

There are many different reasons you could have blood in your stool. Hemorrhoids, or swollen veins in the lower rectum, are a common cause. Other conditions that can show cause blood in the stool are:

• Rectal prolapse
• Rectal polyps
• Ulcers in the rectum
• Injury to the mucosa (lining tissue) in the colorectal system
• Anal fissures
• Diverticular bleeding
• Inflammatory bowel diseases, such as ulcerative colitis or Crohn’s disease
• Colorectal cancer

“Some of these things, like hemorrhoids, fissures or prolapse, can be related to constipation and straining, or on the other side of the spectrum, they can be related to having a lot of loose stools,” says Richards.

There’s only one way to find the real cause of blood in stool

Even though many problems can cause blood in your stool, there is only one way to check it out properly — a rectal exam and colonoscopy.

“The investigative part is straightforward: we take a look inside and out,” says Richards. “With data telling us that more younger people are getting colorectal cancer, most doctors will say, ‘Let’s just do a colonoscopy.’ I know people don’t want to hear that, but my priority is to make sure I don’t miss anything.”

A colonoscopy is an exam of the whole large intestine (colon) and rectum, which is done while you are sedated. It requires preparation, which includes drinking a laxative solution to clean out your colon.

“I know colonoscopies are not the most fun thing to do, but most people can tolerate it pretty easily. The procedure is not very long, and the recovery is short,” says Richards. “If you’re 45 or older, it’s recommended you have a colonoscopy every 10 years even if you don’t have symptoms. If you’re under 45, I would do it to be sure of what’s going on. I don’t like unanswered questions.”

Pay attention to what the blood looks like

Blood in the stool can also show up in a variety of ways, and what the blood looks like can give clues to what’s going on in your body.

An adult’s digestive system, including the esophagus, stomach and intestines, can be as long as 30 feet, and the blood in your stool can come from any part along it. A good description of the look and amount of blood can help your doctor identify the problem.

“Bright red blood might be something low in the colon or rectum like diverticular bleeding or hemorrhoids, darker blood may be from higher up in the colon,” says Richards. “If the blood is more black or tar-like, that might signal an issue in the small intestine or stomach.”

If you only have blood on the tissue when you wipe but not in your stool, this is more likely to be hemorrhoids or anal fissures, which should be confirmed by your doctor.

Blood from polyps or colorectal cancer can show up in various ways. If a polyp or tumor is low in the rectum, you may see bright red blood similar to what can be seen with hemorrhoids. 

Slowly bleeding tumors at the beginning of the colon may result in dark red or black stools. Or tumors may lose microscopic amounts of blood that may make your stool just a little bit darker or that may not change the color of the stool at all.

Intermittent blood should still be checked out

Blood in your stool may come and go, but that does not mean it should be ignored.

“It can feel very personal to talk about blood in your stool, so it’s tempting to wait to see if it goes away on its own,” says Richards. “But cancers can bleed for a while and then stop, so don’t put off talking to your doctor just because blood stops.”

Note any other symptoms you have

You might have other symptoms linked to the blood in your stool. Take note of body changes and discuss everything with your doctor.

Here are some additional signs that the blood in your stool may be more worrisome:

• Anemia and/or feeling light-headed
• Chest pain and shortness of breath
• Pain in your abdomen, pelvis or rectum
• Fevers
• Nausea and vomiting
• Pain or difficulty with swallowing
• Jaundice
• Significant unexplained weight loss

Listen to your body

Many health problems exist even before symptoms start, says Richards. That means when you do have symptoms, they must be taken seriously.

“We know there are people out there who have colorectal cancer and don’t have any symptoms at all,” says Richards. “If you see blood in your stool, your body is telling you something. Don’t ignore it.”

Request an appointment at MD Anderson online or by calling 1-877-632-6789.