Bloody Diarrhea: What It Means & When It’s Serious

Key takeaways:

• Bloody diarrhea can have many causes, including irritable bowel syndrome, anal fissures, hemorrhoids, or infections.
• While some of its causes aren’t serious, bloody diarrhea is always something you should report to your doctor.
• Some causes of bloody diarrhea can be preventable with dietary changes and improved hygiene.

Bloody diarrhea can be alarming, but understanding what it could mean is important to staying healthy.

Conditions such as irritable bowel syndrome and infections like the stomach flu are common causes of diarrhea, which may sometimes contain blood. Anal fissures and hemorrhoids are also relatively common causes of blood in your stool.

However, some causes of bloody diarrhea are serious and require medical intervention. That means identifying the potential concerns related to your diarrhea is important.

Is bloody diarrhea normal?

Experiencing diarrhea can be common in individuals with irritable bowel syndrome or cases of stomach bugs. However, when diarrhea contains blood, it should raise concerns.

Bloody diarrhea can occur due to a variety of reasons, ranging from hemorrhoids and anal fissures to serious gastrointestinal issues such as colorectal cancer and chronic inflammatory bowel disease. Understanding these causes is the first step toward addressing the condition effectively and knowing when to seek medical attention.

Common causes of bloody diarrhea

The causes of bloody diarrhea can range from benign to serious, with serious causes requiring urgent medical attention. Let’s review some of the most common reasons you may experience bloody diarrhea and which of those causes requires prompt medical attention.

Hemorrhoids

Hemorrhoids refer to inflamed veins of the anus and rectum. Hemorrhoids may be internal or external and vary in severity. Some of the causes of hemorrhoids include low-fiber diets, straining during bowel movements, and heavy lifting.

Bleeding from your rectum and seeing bright red blood on the stool or toilet paper with a bowel movement is a common hallmark of hemorrhoids. Treatment for hemorrhoids can vary from basic dietary adjustments to the need for surgical intervention, so you should always speak with your healthcare provider if your symptoms are ongoing and causing severe pain or blood loss.

Inflammatory bowel disease

Inflammatory bowel disease is a condition that causes chronic inflammation of the gastrointestinal tract. It consists of two different disease processes known as ulcerative colitis and Crohn’s disease. Diarrhea is a common symptom of both diseases.

However, you are more likely to experience bloody diarrhea with or without mucus in ulcerative colitis than in Crohn's disease. Inflammatory bowel disease requires the intervention of a healthcare provider but is not considered a medical emergency.

Infection

Drinking contaminated water or eating contaminated food can lead to certain bacterial or viral gastrointestinal infections that cause bloody diarrhea.

Shigella bacteria can cause an infection called shigellosis, and this condition commonly results in bloody diarrhea. Shigella bacteria can also spread from an infected individual to others through close contact.

Colon cancer

Rectal bleeding or blood in the stool can sometimes indicate an increased chance of colorectal cancer. If you are experiencing bright red bloody diarrhea, you should be evaluated by a healthcare provider to rule out the possibility of colorectal cancer.

What bloody diarrhea may mean based on appearance, consistency, or another symptom or condition

Bloody diarrhea can indicate different health conditions and causes that need to be properly identified to receive the correct treatment. Additional details about appearance, consistency, or other symptoms can help your healthcare provider make an accurate diagnosis. Here are some common presentations to look for and what they might mean.

• Dark red bloody diarrhea: Dark red blood usually comes from the presence of old or digested blood associated with bleeding from the upper gastrointestinal tract. Peptic ulcer disease is a common cause.
• Bright red bloody diarrhea: Bright red blood indicates the presence of blood coming from the lower gastrointestinal tract, such as the rectum or colon. Bright red blood is usually caused by hemorrhoids or inflammatory bowel disease but may also indicate colon cancer.
• Bloody diarrhea with mucus: Bloody diarrhea with mucus is a common symptom of ulcerative colitis.
• Bloody, watery, or liquidy diarrhea: This type of diarrhea can be a sign of gastrointestinal infections. If watery or liquid diarrhea occurs frequently, it can lead to dehydration and is a reason for prompt medical evaluation.
• Bloody diarrhea accompanied by vomiting: Vomiting that comes with bloody diarrhea can occur in some cases of inflammatory bowel disease. Experiencing these two symptoms together may also indicate an infection.
• Bloody diarrhea accompanied by stomach cramps: Stomach cramps with bloody diarrhea can be due to diverticulitis, inflammatory bowel disease, or infection.
• Bloody diarrhea that occurs during pregnancy: Hemorrhoids are a common occurrence during pregnancy and may lead to bloody diarrhea. However, any pregnant person experiencing bloody diarrhea should consult their healthcare provider to rule out more serious potential causes.

Read our guides on types of diarrhea and stool colors for more.

When to see a doctor about bloody diarrhea

Although the cause of bloody diarrhea may be something benign, such as a hemorrhoid, you should never ignore it. Symptoms that worsen or do not resolve on their own may require medical attention.

You should see a doctor if:

• You experience bloody diarrhea on more than one occasion.
• You notice pain with bowel movements.
• You are experiencing additional symptoms such as abdominal pain, nausea, or vomiting.
• You have other vague symptoms, such as weakness and weight loss.
• You have a family history of colorectal cancer.

You should go to the emergency room if:

• You see large amounts of blood in your stool.
• You experience severe pain with bowel movements.
• You are also experiencing a high fever.
• You are pregnant and experience bloody diarrhea.

Questions to ask your doctor about bloody diarrhea

• What could be causing my bloody diarrhea?
• What types of testing will you conduct to diagnose the cause of my symptoms?
• What treatment options are available?
• What red flags should I look for that would indicate the need for a follow-up appointment?

How to stop or treat bloody diarrhea

Depending on the cause of your bloody diarrhea, you may be able to manage your symptoms at home. Lifestyle changes and following the advice of your doctor can help you get rid of diarrhea.

Medications

If you are experiencing hemorrhoids, your doctor may recommend stool softeners to minimize straining during bowel movements.

Fiber supplements can also be helpful in these cases. Long-term prescription medications, including steroids, biologics, and immunomodulators, are likely to be prescribed in the case of inflammatory bowel disease. Infections may be treated with antibiotics if bacteria are behind your symptoms.

Dietary changes

Eating a low-fiber diet can lead to straining with bowel movements and an increased likelihood of developing hemorrhoids. Making dietary changes to incorporate more fiber into your diet can help if hemorrhoids are found to be the cause of your bloody diarrhea.

Hydration

Excessive diarrhea is a common cause of dehydration. If you are experiencing frequent and ongoing episodes of diarrhea, this can lead to a quick loss of fluids and electrolytes. It is important to stay hydrated and drink plenty of fluids and solutions containing electrolytes if you are experiencing diarrhea.

How to prevent bloody diarrhea

Some causes of bloody diarrhea may be preventable, while other causes cannot be controlled. Below are a few suggestions for staying ahead of bloody diarrhea.

Diet

Maintaining a diet high in fiber can minimize the chances of hemorrhoids. Diet is also an important consideration when it comes to avoiding food contamination. Only drink fluids and consume foods from sources that you are familiar with.

Yearly screening tests

Making sure you see your primary care provider for yearly check-ups is extremely important in both preventing and treating disease.

Always remain up to date with all of your age-appropriate screening tests. Exams such as a colonoscopy will not necessarily prevent colorectal cancer, but they can help you catch it earlier and during the more treatable stages.

Hygiene

Practicing good hygiene and frequent hand washing can help prevent the spread of viral and bacterial infections that cause stomach bugs. Pay close attention to the source of your food and water to make sure you are consuming only clean food and drinks that are less likely to be contaminated and cause food poisoning.

Frequently asked questions: bloody diarrhea

You likely still have some questions regarding bloody diarrhea. Here are the answers to some of the most commonly asked questions about this unpleasant symptom.

Can a stomach bug cause bloody diarrhea?

Yes, gastroenteritis, also referred to as the stomach bug, can sometimes lead to bloody diarrhea. This is usually due to inflammation in the intestines and will subside when the infection resolves.

How long can blood in diarrhea last?

The duration of blood in diarrhea can vary based on the underlying cause. It may persist as long as the underlying cause remains undiagnosed and untreated. If this symptom lasts for more than a few days, medical attention is necessary.

Final thoughts

Bloody diarrhea is a symptom that should never be overlooked. By understanding its potential causes and recognizing when to seek help, you can ensure that you receive the appropriate care. Whether it’s a minor infection or a more serious condition, being informed empowers you to take action and prioritize your health.

General Medicine follows a strict editorial process, including using real experts to write our articles, vetted primary sources, fact-checking, a secondary medical review, and updates as necessary. This article was medically reviewed and fact checked by Dr. Lane Thaut, DO.

Sources

“About Shigella Infection.” CDC, 16 Feb. 2024, www.cdc.gov/shigella/about/index.html. Accessed 21 Oct. 2024.

Fritz, Cassandra D L, et al. “Red-flag signs and symptoms for earlier diagnosis of early-onset colorectal cancer.” Journal of the National Cancer Institute vol. 115,8 (2023): 909-916. doi:10.1093/jnci/djad068, https://pubmed.ncbi.nlm.nih.gov/37138415/.

“Hemorrhoids.” Medlineplus.gov, 13 Nov. 2023, medlineplus.gov/hemorrhoids.html. Accessed 21 Oct. 2024.

“Inflammatory Bowel Disease (IBD).” CDC, 10 July 2024, www.cdc.gov/inflammatory-bowel-disease/. Accessed 21 Oct. 2024.

McDowell, Christopher, et al. “Inflammatory Bowel Disease.” StatPearls, StatPearls Publishing, 4 August 2023, https://pubmed.ncbi.nlm.nih.gov/29262182/.