Read below about bloody diarrhea, including causes, treatment options and remedies. Or get a personalized analysis of your bloody diarrhea from our A.I. health assistant. At Buoy, we build tools that help you know what’s wrong right now and how to get the right care.

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Bloody Diarrhea Symptoms

Although this is probably not a favored topic of discussion, it is not uncommon to notice blood —– even a small amount of bright red blood — in your stool from time to time. Typically, this is caused by conditions such as hemorrhoids (enlarged blood vessels in the rectum or anus) or anal fissures (tears or cracks in the tissue lining the anus or rectum).

Diarrhea is also common condition experienced by just about everyone several times during their lives. Most of the time, diarrhea occurs due to infection or from foods that disagree with you. Bloody diarrhea, on the other hand, is not so common or normal, and requires professional medical care.

Bloody diarrhea may or may not be accompanied by nausea, vomiting, fever, chills, stomach pain, fatigue, severe anemia, dizziness, weakness, shortness of breath, chest pain, or headache.

In most occurrences, bloody diarrhea is a sign of intestinal infection; sometimes, it can be an indication of a more serious condition, such as cancer or a vascular problem with your bowels. Let’s look at the infections and non-infectious causes of bloody diarrhea.

Bloody Diarrhea Causes Overview

Infections:

  • Bacterial infections
  • Enterohemorrhagic Escherichia coli (EHEC) – There are many strains of the bacteria E. coli. Some strains of E. coli normally live in your intestines and do not cause illness. Some strains of E. coli can release shiga toxin and make you very sick with stomach pain, bloody diarrhea and even kidney failure.

    • Shigella
    • Campylobacter
    • Salmonella
  • Viral infections:

    • These are probably the most common infections to give you bloody stools and many viruses are capable of doing this, like Norovirus, Rotavirus and Adenovirus.
  • Parasitic infections

    • Infections with parasites like Entamoeba histolytica and Giardia Lamblia (common in hikers who drink water with beaver poop in it!) can lead to bloody diarrhea.

Serious non-infectious conditions:

  • Ischemic colitis – is a condition in which the blood flow to the large intestine is restricted. This may cause damage to your colon – damage severe enough to cause bloody diarrhea and even necrosis (death) of all or part of your colon. This is usually associated with severe abdominal pain and often occurs in people with a history of vascular disease elsewhere in the body.

  • Inflammatory Bowel Disease

    • Bloody diarrhea that is a result of a chronic disease process, such as inflammatory bowel disease (IBD), often lasts weeks or months and is associated with weight loss and feeling unwell. This can also cause you to lose blood and become anemic. Crohn's Disease and Ulcerative Colitis are the two most common types of IBD and both require the specialized care of a doctor called a gastroenterologist.
  • Colon cancer

    • Colon cancer can cause both diarrhea (which may or may not be bloody) and constipation. Other symptoms associated with colon cancer include a change in bowel habits, stomach pain, fatigue, weight loss and anemia.

Anal and rectal causes of bloody diarrhea:

  • Hemorrhoids are a common cause of blood on the toilet paper and on the outside of the stool, though they can also cause blood to be present in loose stools and diarrhea. Usually you will have pain, itching or even feel these near the anus.

  • Anal fissures can bleed and are usually associated with severe pain with bowel movements or pain after a bowel movement. This is a crack or tears in the anus and it can bleed, lead to blood on the toilet paper and in the stool.

Neither condition is life threatening, but both of these need medical care so you can feel better and not make these worse.

A.I. Health Assistant Causes for Bloody Diarrhea

The list below shows results from the use of our A.I. Health Assistant by Buoy users who experienced bloody diarrhea. This list does not constitute medical advice.

  1. 1.Food Poisoning

    Food poisoning is a common ailment that causes gastrointestinal symptoms like nausea, vomiting, and diarrhea. It is caused by improperly handled or unrefrigerated food.

    1-3 days

    Rarity:
    Common
    Top Symptoms:
    nausea, abdominal pain (stomach ache), headache, abdominal cramps (stomach cramps), dizziness
    Symptoms that never occur with food poisoning:
    severe fever, being severely ill, bloody diarrhea
    Urgency:
    Self-treatment
  2. 2.E. Coli Infection

    EHEC, or Enterhemorrhagic Escherichia coli, is a strain of bacterium that can be acquired worldwide through eating contaminated food, especially undercooked ground beef, raw produce, or ready-to-eat cold meats. Contracting this type of bacterium may lead to bloody diarrhea and severe pain the abdomen.

    With timely treatment, the disease will resolve within 2 to 5 days.

    Rarity:
    Ultra rare
    Top Symptoms:
    diarrhea, abdominal cramps (stomach cramps), being severely ill, general abdominal pain, fever
    Urgency:
    In-person visit
  3. 3.Intestinal Infection With Ameba Parasite

    Visiting or living in places with poor sanitation can lead to parasite infections that can cause long-lasting diarrhea and stomach pain.

    More than 90% of the time, parasites goes away on its own over the course of 6 weeks.

    Rarity:
    Rare
    Top Symptoms:
    nausea, loss of appetite, diarrhea, constipation, general abdominal pain
    Urgency:
    Primary care doctor
  4. 4.Diarrhea Caused by a Bacteria Called Vibrio

    Vibrio parahaemolyticus is a bacterium in the same family as those that cause cholera and Vibrio vulnificus. It can be contracted by consuming raw or undercooked shellfish, or exposure to sea or brackish water, and causes gastrointestinal illness (i.e. diarrhea often with abdominal cramping, nausea, vomiting, fever and chills) in humans.

    Symptoms will usually resolve within 2 to 3 days without antibiotics.

    Rarity:
    Rare
    Top Symptoms:
    diarrhea, nausea, stomach bloating, headache, abdominal cramps (stomach cramps)
    Symptoms that always occur with diarrhea caused by a bacteria called vibrio:
    diarrhea
    Urgency:
    Self-treatment
  5. 5.Campylobacter Small Intestine Infection

    Infection with the Campylobacter bacterium is one of the leading causes of acute diarrhea worldwide. The risk for this infection is increased in people with HIV/AIDS.

    The diarrhea can subside within 7 days without treatment, but antibiotic treatment is recommended for faster recovery and avoidance of complications.

    Rarity:
    Rare
    Top Symptoms:
    diarrhea, abdominal cramps (stomach cramps), general abdominal pain, fever, severe diarrhea
    Symptoms that always occur with campylobacter small intestine infection:
    diarrhea
    Urgency:
    Primary care doctor

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  6. 6.Ulcerative Colitis

    Ulcerative Colitis (UC) is a condition that causes diarrhea, abdominal pain, and bloody bowel movements. These symptoms occur because the large intestine (colon) has become inflamed and acquired sores, known as “ulcers.”

    Chronic

    Rarity:
    Rare
    Top Symptoms:
    nausea or vomiting, diarrhea, general abdominal pain, fever, back pain
    Urgency:
    Primary care doctor
  7. 7.New Onset Crohn's Disease

    Crohn's disease is a disorder caused by chronic inflammation in the digestive tract. The damaging inflammation causes abdominal pain, diarrhea, weight loss, and malnutrition.

    Not expected to reduce life expectancy

    Rarity:
    Rare
    Top Symptoms:
    fatigue, stomach bloating, loss of appetite, constipation, abdominal cramps (stomach cramps)
    Urgency:
    Primary care doctor
  8. 8.Bacterial Infection Caused by Clostridium Difficile

    Antibiotic use can disrupt the normal microorganisms that inhabit the human digestive tract, and a bacterium called Clostridium difficile can grow out of control in the intestines. Though relatively rare compared to other bacterial infections, C. Difficile is one of the leading causes of infectious diarrhea in the United States.

    Fever and diarrhea should respond within 4 to 6 days upon beginning treatment.

    Rarity:
    Rare
    Top Symptoms:
    abdominal pain (stomach ache), abdominal cramps (stomach cramps), being severely ill, fever, watery diarrhea
    Urgency:
    In-person visit
  9. 9.Colon Damage From Impaired Blood Flow

    A specific type of colon damage, called ischemic colitis occurs when blood flow to part of the large intestine (colon) is reduced due to narrowed or blocked blood vessels (arteries). The diminished blood flow provides insufficient oxygen for the cells in the digestive system. It can cause pain and can damage the colon. Ischemic colitis can affect any part of the colon, but most people experience pain on the left side of the belly area (abdomen). It is most common among people older than age 60. Commonly, ischemic colitis is misdiagnosed because it can easily be confused with other digestive problems.

    Ischemia of the colon has the best prognosis of the ischemic bowel diseases. However, 20% of people develop chronic ulcers as a result. You should make sure to follow up with your doctor to manage the disease and avoid complications.

    Rarity:
    Rare
    Top Symptoms:
    abdominal pain (stomach ache), nausea, loss of appetite, diarrhea, being severely ill
    Urgency:
    Hospital emergency room
  10. 10.Hemolytic Uremic Syndrome

    Hemolytic-uremic syndrome (HUS) is a disorder that usually occurs when an infection in the digestive system produces toxic substances that destroy red blood cells, causing kidney injury.

    Indefinite

    Rarity:
    Ultra rare
    Top Symptoms:
    abdominal pain (stomach ache), fatigue, nausea, diarrhea, being severely ill
    Symptoms that always occur with hemolytic uremic syndrome:
    being severely ill
    Urgency:
    Hospital emergency room

Bloody Diarrhea Treatments and Relief

You should seek immediate care for bloody diarrhea if you:

  • have had it for more than 24 hours
  • have diarrhea that is dark red or black
  • have severe abdominal pain
  • have signs of dehydration (dry mouth, dizziness, confusion, muscle cramping, excessive thirst)
  • have a fever (>100.4)
  • are over 65 years old
  • are pregnant
  • are currently or have recently finished taking a course of antibiotics

The treatment of bloody diarrhea requires addressing the underlying cause.

  • Avoid using anti-diarrheal medications such as loperamide or bismuth salicylate and diphenoxylate. These medications can complicate EHEC infections.
  • Stop taking any antibiotics.
  • Avoid NSAIDS (non-steroidal anti-inflammatory drugs such as ibuprofen), smoking, alcohol use, aspirin, anticoagulants, and anti-platelet agents.

As with any diarrhea, it is important to stay well hydrated and well nourished. It is equally important to replace electrolytes, especially sodium and potassium and this can be done with commercial sports beverages, bullion and fluids containing sodium and potassium.

FAQs About Bloody Diarrhea

Here are some frequently asked questions about bloody diarrhea.

What foods can cause blood in stool?

Only foods that contain a large amount of blood (blood sausage, blood pudding), foods that contain large amounts of heme (or the chemical in blood that holds oxygen), or foods that cause laceration to the bowel cause blood in the stool. Sharp items that are not food — glass, stones, metal — can lacerate the bowel causing blood in the stool. Other foods can cause ulcers in the GI tract. Foods that are very high in acid, or foods that cause "metaplasia" or changing of the structure of cells can over the long term, can lead to bleeding.

Can constipation cause blood in stool?

Constipation by itself does not cause blood in the stool. However, passing a particularly large stool may cause an anal fissure which usually presents with bright red blood on the tissue or in the toilet. If you have a history of hemorrhoids, passing hard stool can cause rupture of a hemorrhoid and dark red blood either on the stool or in the toilet. Finally, long term constipation can cause outpouchings of the intestines (diverticulosis) exposing blood vessels and causing dark red blood in the stool.

Can hemorrhoids cause bleeding in the stool?

Yes, hemorrhoids can cause bleeding either in the bowel, streaked on the feces, or on the toilet paper. Bleeding from hemorrhoids is usually painless and often happens sometime after a bowel movement but can be unprovoked. The blood may drip into the toilet and tinge the color of the water. Bleeding can also occur in large amounts which is worsened by straining.

Can certain antibiotics cause bloody diarrhea?

No. However, some antibiotics can alter the color of feces. Antibiotics do not affect the lining of the gut in such a way as to cause rupture. They may, however, cause cramping or bloating (from a lack gut mobility) or diarrhea from an increase in mobility. However, antibiotics can cause a form of infectious diarrhea, C. difficile, that infrequently may be associated with bleeding.

When should you see a doctor for bloody stool?

You should see a doctor if you are concerned about blood in your stool. You should visit the emergency room if there is a large amount of blood, if the blood is dark red or looks like coffee grounds or dark red sludge, or if you experience any lightheadedness, dizziness, or cold and clammy sensation or vomit blood.

Questions Your Doctor May Ask About Bloody Diarrhea

  • Q.Any fever today or during the last week?
  • Q.Have you experienced any nausea?
  • Q.Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
  • Q.Have you lost your appetite recently?

If you've answered yes to one or more of these questions, try our bloody diarrhea symptom checker to find out more.

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Bloody Diarrhea Symptom Checker Statistics

  • People who have experienced bloody diarrhea have also experienced:

    • 20% Abdominal Pain (Stomach Ache)
    • 14% Abdominal Cramps (Stomach Cramps)
    • 6% Nausea
  • People who have experienced bloody diarrhea had symptoms persist for:

    • 38% Less Than a Week
    • 37% Less Than a Day
    • 10% Over a Month
  • People who have experienced bloody diarrhea were most often matched with:

    • 50% E. Coli Infection
    • 40% Intestinal Infection With Ameba Parasite
    • 10% Food Poisoning
  • Source: Aggregated and anonymized results from visits to the Buoy AI health assistant (check it out by clicking on “Take Quiz”).

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