What causes blood in stool?

Blood in their stool is a symptom that can affect both men and women for a large range of reasons. The MediFind Medical Team has summarized 10 potential causes for extreme fatigue below in order from most to least likely based on our data. Learn more about how MediFind works here. You can also enter your symptoms into MediFind’s Symptom Checker to receive more customized results.

Crohn’s Disease

Chronic inflammation of the digestive tract, also called Crohn’s disease, causes symptoms like severe diarrhea and abdominal pain. These bouts of persistent diarrhea, specifically, can cause abrasions that lead to blood in stool. Though it does not involve internal bleeding, it is a sign of an autoimmune disorder that affects many people across the globe. Gastrointestinal doctors have no cure for the disease, but can instead target the symptoms, using anti-inflammatory drugs and immune suppressors, to the point that patients feel as if they are in complete remission. Find a gastrointestinal doctor near you here.

Gastrointestinal Bleeding

Originating from some sort of damage at the GI tract, blood in the stool can reflect further internal damage. This bleeding can start at the upper torso: the esophagus, stomach, and small intestine or instead begin at the lower GI: the small intestine, large intestine, rectum, and anus. The source of the bleeding may occur from anal fissures or hemorrhoids but it may also refer to serious cancers. As this may be an emergency condition, a gastrointestinal doctor would first ensure that the patient has adequate blood levels before starting tests to isolate the location of the bleed. Find a gastrointestinal doctor near you here.

Anal Fissure

Patients can experience blood in their stool if they had torn or split the mucosal lining of their anus. Much like the fissures one sees on cliff faces, these tears bleed persistently but also heal quickly. They are caused from passing large, hard stools or due to persistent diarrhea and are very common in infants. Women may also experience them after childbirth. This condition heals on its own and does not require medical intervention. However, a gastrointestinal doctor may recommend stool softeners or minor surgery in chronic cases. Find a gastrointestinal doctor near you here.

Diverticula of the Small Intestine

The walls of the large intestine are not completely smooth and can in fact bellow out sac-like protrusions called diverticula. These are normal and asymptomatic but can become severe and life threatening. The diverticula become sources of bleeding that can present as blood in the stool. A gastrointestinal doctor will focus on fluid and electrolyte management for treatment. Find a gastrointestinal doctor near you here.

Intestinal Ischemia

When blood vessels are partially or fully blocked, intestinal blood flow also decreases and leads to intestinal tissue damage. As the blood is not being collected, it can accumulate with patient stool causing blood in the stool as a symptom along with severe pain that makes it difficult to sit still. This condition is dangerous and can lead to death if not properly treated. A gastrointestinal doctor will likely perform surgery if they determine internal bleeding; their primary goal is to stop the ischemia. Find a gastrointestinal doctor near you here.

Colorectal Cancer

Blood in the stool, particularly if it is chronic, can also be an indicator of multiple cancers. Colorectal cancer, or cancer of the colon, affects the large intestine or rectum. It can be benign, appearing as non-cancerous polyps, or growths, or become malignant adenomas that develop into adenocarcinomas. A gastrointestinal doctor has multiple available treatments for colorectal cancer, oftentimes emphasizing removal of the polyps and chemotherapy. Partial or complete excision of the colon is another alternative. Find a gastrointestinal doctor near you here.


The anus and rectum have significant blood supply, which can leak into the stool when the veins become inflamed. These are called hemorrhoids and can be completely asymptomatic. However, as the blood begins to clot, they become quite painful, making it very difficult to pass bowel movements. A gastrointestinal doctor will prescribe hemorrhoid creams that reduce pain alongside stool softeners and corticosteroids to drop the swelling. As hemorrhoids tend to pass on their own, home treatments tend to be sufficient. If they recur or do not improve, removal of the hemorrhoid through surgery may be required. Find a gastrointestinal doctor near you here.


The bone marrow, where the progenitors to cells are made, stem cells, can experience a type of blood cancer called leukemia. The cancer affects white blood cells, which help protect the body from infection. Since these blood cells travel through the bloodstream, the cancer can also spread to other parts of the body. Blood in the stool is one of many symptoms of leukemia, alongside fatigue and muscle weakness. An oncologist will prescribe chemotherapy depending on the type of leukemia. Find an oncologist near you here.

Pneumatosis Coli

When gas accumulates inside the wall of the small or large intestine, it can result in tissue damage that appears as blood in the stool. This is called pneumatosis coli or intestinalis and very little is known about its cause. The illness can develop into intestinal ischemia or obstruction, which can lead to more severe outcomes. Generally, it is asymptomatic and is more often seen in premature infants. A gastrointestinal doctor will prescribe antibiotics such as metronidazole as it appears the gas may originate from bacteria. Find a gastrointestinal doctor near you here.

Ulcerative Colitis

Falling into the same family of chronic inflammatory bowel disease as Crohn’s disease, ulcerative colitis involves the development of ulcers alongside the digestive tract, colon, and rectum. Different types of colitis refer to where in the digestive tract the ulcers are forming, which range from mild to severe. Alongside blood in the stool, other symptoms include fatigue, loss of appetite, nausea, and problems passing bowel movements. Like Crohn’s disease, there is no known treatment for ulcerative colitis but a gastrointestinal doctor will prescribe anti-inflammatory drugs along with immunosuppresors. Find a gastrointestinal doctor near you here.

Understanding the Results

These results are based on the most likely conditions for a 20 to 40 year-old patient that is living in the United States. Our data shows that 96% of the time, this symptom is related to one of the 10 most likely causes. Location and age can also contribute to different results. Use our Symptom Checker to add your information and get your custom results.

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Differences in Age Groups

Many conditions that result in blood in the stool involve infants as their bodies are still acclimating to the introduction of new bacteria. Among adults, illness appears to target the elderly, particularly with regard to cancers, but adults around the age of 30 are also susceptible to inflammatory bowel disease.

Differences among Men and Women

There appears to be no major difference between men and women. However, as men have a greater tendency to eat a lot of red meat; gastrointestinal issues appear to be more common among them.

Last Updated: December 08, 2022

Published By: MediFind Medical Staff