Blood in Stool: What It Means and How to Treat It

Updated on 2024-03-14 19:30:44 0 0

14 Possible Causes of Blood in Stool

By Naveed Saleh, MD, MS

Medically reviewed by Jay N. Yepuri, MD

Blood in stool happens when there is bleeding in the gastrointestinal (GI) tract. Peptic ulcer disease, anal fissures, hemorrhoids, and cancer can cause blood in stool. Blood in stool for a woman is usually the same as it is for men since GI conditions affect people of all sexes.

Blood in stool looks red or maroonish. Blood that comes from the upper GI tract and is digested as it moves through the gut can look darker, often black and tar-like.1

It can be a sign of something serious, so blood in your stool should never be ignored. You should always tell your provider if you have blood in your stool. They can do a physical exam, lab tests, and ask you about your health history to find out the cause.

This article discusses some of the possible reasons for blood in stool, as well as how these causes can be diagnosed and treated.

Verywell / Laura Porter

Upper GI Bleed

Blood in your stool may come from somewhere in your upper GI tract that is bleeding. The most common cause is peptic ulcer disease.2 In this condition, there are sores in the lining of the stomach or upper intestine that bleed. Blood from a peptic ulcer can be red or darker in color—even black and tarry.

An upper GI bleed can be diagnosed with a test called an endoscopy.3 During the procedure, a gastroenterologist looks at your upper GI tract with a camera attached to a narrow, flexible tube. The tube is put down your throat and looks at your gut.

If you have serious upper GI bleeding, you will need surgery to fix it.4

Anal Fissure

Anal fissures are the most common cause of bloody stool in infants, but adults can get them, too.5

Anal fissures are cracks in the skin that can bleed. The tears are often caused by constipation, or having large, firm stools that are hard to pass. The stretching skin of the anus makes fissures visible.

Anal fissures usually heal on their own.6 You can treat the pain and discomfort with petroleum jelly. Drinking more water and eating high-fiber foods can help soften your stools and prevent anal fissures from happening again.

Polyps

A polyp is a small growth on the lining of your intestines. There are a few types of polyps, but adenomatous polyps are the most common. These polyps grow on the lining of the colon (large intestine). About 25% of adults aged 50 and over have this type of polyp.7

Adenomatous polyps can turn into colorectal cancer. Colorectal cancer is the third most common cause of cancer-related deaths in the United States.8

Although most cases of colorectal cancer develop from adenomatous polyps, only around 5% of polyps will become cancerous.9

Polyps often have no symptoms, but sometimes they can cause bloody stools. The blood can be red or dark and tarry.

Polyps can be removed before they become cancerous. If they do progress to cancer, the cancer is treatable if caught early. This is why all people age 45 and older should be regularly screened for colorectal cancer.10 This can be done with a colonoscopy or stool-based test.

Hemorrhoids

Hemorrhoids are swollen blood vessels that bulge from the anus. Hemorrhoids are often uncomfortable and can be painful or itchy. There are a lot of blood vessels around the anus and rectum, so hemorrhoids can bleed bright, red blood.

You might be more likely to have hemorrhoids if you:

Have chronic diarrhea
Are frequently constipated
Do a lot of heavy lifting
Sit for long periods of time
Are pregnant

Most hemorrhoids do not require surgery. Eating more fiber or using a salve like Preparation H can help with symptoms. However, surgery is an option if your hemorrhoids are severe.11

Gastroenteritis

Gastroenteritis is an illness of the stomach and intestines that causes inflammation. It can be caused by a virus, bacteria, or parasite. Sometimes, gastroenteritis causes bloody diarrhea—especially bacterial gastroenteritis.12

Food poisoning is a type of gastroenteritis. Bacteria that commonly cause food poisoning include:

Campylobacter
E. coli
Listeria
Salmonella

Most of the time, gastroenteritis gets better on its own, but you should call your provider if symptoms last for more than one or two days.

Angiodysplasia

Blood in stool that cannot be explained is often caused by angiodysplasia. Angiodysplasia can happen as the blood vessels in the gut age or weaken. This type of blood in stool can be red or dark and tarry.

Angiodysplasia is common during end-stage renal disease (kidney disease) or renal failure. People with a genetic bleeding disorder called von Willebrand disease can also have angiodysplasia.13

Angiodysplasia can be treated in a few ways, including:

Removal during endoscopy
Hormone therapy
Blood transfusions
Iron supplements14

For most people, angiodysplasia disappears on its own.

Inflammatory Bowel Disease (IBD)

Inflammatory bowel disease (IBD) is an autoimmune disease that affects the GI tract. With IBD, your immune system attacks and causes inflammation and damage to your intestines. Crohn's disease and ulcerative colitis are the two most common types of IBD.15 Symptoms of IBD can include blood in stool which can be red or dark and tarry.

IBD can be treated in a few ways:

Steroids
Immune-modifying agents
Surgery

Newer drugs are reducing the number of IBD patients who need surgery, but it can be necessary for people with more severe cases.16

Cancer

Blood in stool can be a sign of colorectal cancer. Bloody stool related to cancer can be red or dark and tarry.

Providers used to think that colorectal cancer mostly happened to people over the age of 50. However, recent studies have shown that it’s also the third leading cause of cancer-related death in adults under the age of 50.17

With earlier detection and treatment, the five-year survival rate for patients with colorectal cancer has been getting higher over time.18

Diverticular Disease

Diverticula are abnormal pouches that form in your lower intestine. There are two types of diverticular disease: diverticulosis and diverticulitis. Having diverticula is called diverticulosis. If the diverticula gets infected or inflamed, it’s called diverticulitis.19

Both forms of diverticular disease can cause pain and blood in stool. When diverticular disease causes bleeding, it will usually start suddenly and be red or maroon in color.20

Diverticula happens when the wall of your colon is weak. Sometimes, they can become very large—up to several centimeters in size.21 The disease is often blamed on a low-fiber diet, but the true cause of diverticulitis is unknown.

A surgeon can stop bleeding from diverticula during an endoscopy or abdominal surgery. Diverticula can be treated in or out of a hospital, depending on how sick a person is. Diverticulitis can often be successfully treated with antibiotics.21

Ischemic Colitis

Ischemic colitis happens when the blood vessels that supply the large intestine are narrowed or blocked. Most cases of ischemic colitis happen in older adults. The condition can be short-term or long-term.

Blood in stool that’s bright red is a common symptom of ischemic colitis. Other symptoms include:

Red blood in the stool
Diarrhea
An urgent need to defecate
Abdominal pain and vomiting

Most cases of ischemic colitis do not last long and get better on their own. Sometimes, people with severe cases of ischemic colitis need to be hospitalized. Patients with severe disease may need intravenous (IV) fluids, antibiotics, bowel rest, and a restricted diet.

About 20% of people who develop ischemic colitis end up needing surgery. However, surgery for ischemic colitis is very dangerous—anywhere from 10%-65% of patients who have the surgery die.22

Sexually Transmitted Infections (STIs)

Certain sexually transmitted infections (STIs) can cause blood in stool.23 STIs mostly affect the reproductive tract, but sometimes, they can also cause infection and inflammation in parts of the GI tract—especially the anus and rectum.24

STIs that can cause blood in stool include:25

Syphilis
Gonorrhea
Chlamydia
Herpes
HIV/AIDS

STIs need different treatments, but antibiotics are common. Both partners may need treatment to prevent an STI from coming back.

Anal Sex

Even if you do not get an STI, you could have blood in your stool if your anus or rectum is injured during sex. For example, a tear in the delicate tissue of your rectum could lead to bleeding that you see in your next bowel movement.26

Endometriosis

Endometriosis is a condition in which tissue that is similar to the kind that lines the uterus grows outside the uterus. If the tissue grows on or within the bowel, it can cause GI symptoms.27

In rare cases, blood in stool in women is actually caused by deep endometriosis. For example, because there are lesions of tissue within the rectum. Sometimes, the blood in stool only shows up when a person is menstruating.28

Endometriosis on the bowel often needs to be removed through surgery, though it can come back.

Esophageal Problems

Sometimes, blood in stool is actually caused by a problem higher up in the GI tract. Conditions that affect the food pipe (esophagus) can cause bleeding. If the bleeding gets bad enough, it travels through the digestive system and eventually makes its way out of the body in stool.29

Tears in the esophagus (varices) are examples of conditions that can cause bleeding that may pass through the GI tract. Usually, blood in stool from higher up in the GI tract is darker colored rather than bright red (it may even look black).30

Tears in the esophagus sometimes heal on their own. If they don’t or if there is a major tear, it might take surgery to get the bleeding to stop.

Red Food, Not Blood

Sometimes, what looks like bloody stool is really just red coloring from something you've eaten. Dyes used in foods and drinks like fruit punch and gelatin can make your stool red. Naturally red food like beets can also temporarily color your stool.

When to See a Provider

Anytime there is blood in your stool, you should have it checked out by your healthcare provider. Blood in stool means there’s bleeding somewhere, and it’s important to figure out where it’s coming from and treat the problem.

Summary

Blood in stool is never normal and is always a reason to call your provider. The causes of blood in stool vary but are often related to a problem somewhere in your GI tract. In some cases, conditions outside the GI system can lead to blood in stool. For example, some women have blood in stool because they have endometriosis on their bowel though this is rare. Certain STIs can also cause blood in stool. If you notice blood in your stool, do not wait to seek medical attention.

Sources

Kim BS, Li BT, Engel A, et al. Diagnosis of gastrointestinal bleeding: a practical guide for clinicians. World J Gastrointest Pathophysiol. 2014;5(4):467-78. doi:10.4291/wjgp.v5.i4.467

Saleem S, Thomas AL. Management of upper gastrointestinal bleeding by an internist. Cureus. 2018;10(6):e2878. doi:10.7759/cureus.2878

Sonnenberg A. Timing of endoscopy in gastrointestinal bleeding. United European Gastroenterol J. 2014;2(1):5-9. doi:10.1177/2050640613518773

Jung K, Moon W. Role of endoscopy in acute gastrointestinal bleeding in real clinical practice: an evidence-based review. World J Gastrointest Endosc. 2019;11(2):68-83. doi:10.4253/wjge.v11.i2.68

MedlinePlus. Anal fissure.

Salati, SA. Anal fissure – an extensive update. Pol Przegl Chir 2021;93:1–10. doi: 10.5604/01.3001.0014.7879

Michigan Health. Colon and rectal polyps.

Basch CH, Ethan D, MacLean SA, Garcia P, Basch CE. Readability of colorectal cancer online information: a brief report. Int J Prev Med. 2018;9:77. doi:10.4103/ijpvm.IJPVM_95_18

Harvard Health. They found colon polyps—now what?.

American Cancer Society. American Cancer Society guideline for colorectal cancer screening.

MedlinePlus. Hemorrhoids.

Johns Hopkins Medicine. Bacterial Gastroenteritis.

Muftah M, Mulki R, Dhere T, Keilin S, Chawla S. Diagnostic and therapeutic considerations for obscure gastrointestinal bleeding in patients with chronic kidney disease. Ann Gastroenterol. 2019;32(2):113-123. doi:10.20524/aog.2018.0341

Compagna R, Serra R, Sivero L, et al. Tailored treatment of intestinal angiodysplasia in elderly. Open Med (Wars). 2015;10(1):538-542. doi:10.1515/med-2015-0091

Fakhoury M, Negrulj R, Mooranian A, Al-Salami H. Inflammatory bowel disease: clinical aspects and treatments. J Inflamm Res. 2014;7:113-20. doi:10.2147/JIR.S65979

Crohn's and Colitis Foundation. What is ulcerative colitis?.

Bhandari A, Woodhouse M, Gupta S. Colorectal cancer is a leading cause of cancer incidence and mortality among adults younger than 50 years in the USA: a SEER-based analysis with comparison to other young-onset cancers. Journal of Investigative Medicine. 2017;65:311-315. doi: 10.1136/jim-2016-000229

Brouwer NPM, Bos ACRK, Lemmens VEPP, et al. An overview of 25 years of incidence, treatment and outcome of colorectal cancer patients. Int J Cancer. 2018;143(11):2758–2766. doi:10.1002/ijc.3178

National Institute of Diabetes and Digestive and Kidney Diseases. Diverticular disease.

U.S. Department of Health and Human Services. Diverticular Disease.

MedlinePlus. Diverticulosis and diverticulitis.

FitzGerald JF, Hernandez Iii LO. Ischemic colitis. Clin Colon Rectal Surg. 2015;28(2):93-98. doi:10.1055/s-0035-1549099

Centers for Disease Control and Prevention. Proctitis, proctocolitis, and enterocolitis.

Lamb Ca, Lamb Ei, Mansfield J, Sankar Kn. Sexually transmitted infections manifesting as proctitis. Frontline Gastroenterology. 2012;4(1):32-40. doi:10.1136/flgastro-2012-100274

Sun DJ, Li HT, Ye Z, Xu BB, Li DZ, Wang W. Gastrointestinal bleeding caused by syphilis: A case report. World J Clin Cases. 2021;9(26):7909-7916. doi:10.12998/wjcc.v9.i26.7909

San Franscisco Aids Foundation. What causes pain and bleeding from your butt?.

Endometriosis Foundation of America. Endometriosis symptoms: Gastrointestinal distress.

Keith JJ, Hernandez LO, Maruoka LY, Jethwa T, Lewis JT, George G.A. Pujalte. Catamenial rectal bleeding due to invasive endometriosis: a case report. Journal of Medical Case Reports. 2020;14(1). doi:10.1186/s13256-020-02386-w

Sik B, Li BT, Engel A, et al. Diagnosis of gastrointestinal bleeding: A practical guide for clinicians. World Journal of Gastrointestinal Pathophysiology. 2014;5(4):467-467. doi:10.4291/wjgp.v5.i4.467

NIDDKD. Symptoms and causes of GI bleeding.