Bloody diarrhea occurs when there is blood hidden within loose, watery stools. The appearance of blood can vary depending on the underlying cause. Sometimes, you might notice blood coating the stool, pooling in the toilet bowl, or just showing up as streaks on toilet paper after wiping.

The color of the blood offers important clues. Bright red blood often points to bleeding from the lower colon or rectum, which could be caused by issues like hemorrhoids. If the blood is dark red or even looks almost black and tar-like, it may suggest the bleeding started higher up in the digestive tract—a sign that may indicate a more serious condition.

Your digestive tract can produce blood anywhere along the way, from the mouth to the anus. The cause of bloody diarrhea may be gastrointestinal bleeding due to injury or illness.  Your digestive tract can produce blood anywhere along the way, from the mouth to the anus. The cause of bloody diarrhea may be gastrointestinal bleeding due to injury or illness.

Various factors can cause diarrheal blood, and some of the causes can be dangerous. This article outlines six potential reasons, along with treatments.

What Do the Colors of Blood in Diarrhea Mean?

The appearance of blood in diarrhea can vary in color and offers important clues about where the bleeding might be happening inside your digestive tract:

  • Bright red blood: This typically points to bleeding from the lower part of your colon or rectum. Conditions like hemorrhoids or minor rectal injuries are common sources.
  • Dark red or maroon blood: This may come from slightly higher up in your colon or the lower part of your small intestine. It can signal a more serious problem that should be checked out promptly.
  • Black or tarry stool: When blood spends a longer time traveling through your digestive tract, it turns darker. Black, tar-like stools often suggest bleeding from the stomach or an area higher in the digestive system.

If you notice any of these colors in your stool, especially if they persist, it’s important to seek medical advice to identify and address the underlying cause.

Causes of Bloody Diarrhea in Children

In children, bloody diarrhea often has its own set of culprits, though many overlap with adult causes. One of the most frequent offenders is constipation. Long-term constipation can lead to the development of tiny tears in the lining of the anus, known as anal fissures, or even hemorrhoids—both of which may result in noticeable rectal bleeding.

Beyond constipation, other possible causes include:

  • Inflammatory bowel disease (IBD), which, though less common in young kids, can still occur.
  • Infections from bacteria or viruses that irritate the digestive tract.
  • Congenital conditions like Meckel’s diverticulum—a small pouch in the wall of the lower small intestine that’s present from birth.
  • Gastrointestinal ulcers, which sometimes develop as a result of illness or medication.

Just as with adults, any blood seen in a child’s stool warrants a prompt conversation with a healthcare provider to determine the underlying cause and get the appropriate treatment.

1. Bacteria Infections

A bacteria infection in the digestive tract is one of the most common causes of diarrhea. Most often, the condition occurs in the small intestine, the colon, or both. 

Bacteria infections such as salmonella, shigella, E.coli, and Campylobacter can cause blood in your stools, and these infections are usually very mild and may not even cause symptoms. 

However, if you have blood in your stools, it is essential to see your doctor as soon as possible to get treated.

2. Inflammatory Bowel Disease (IBD)

IBD is a group of inflammatory disorders that affect the digestive tract. In most cases, the symptoms of IBD are diarrhea and constipation. IBD can manifest as:

  • Crohn’s disease
  • Ulcerative colitis

Both Crohn’s disease and ulcerative colitis are forms of IBD, and Crohn’s disease is more common in people with a family history of the disease. Most often, Crohn’s disease appears before the age of 30. Ulcerative colitis is more common in women than men and is diagnosed most often in people between 20 – 40.

Diagnosing IBD is typically done by first doing an endoscopy. The procedure involves inserting a tube with a light and camera into the digestive tract, and the doctor can then see what’s happening inside. 

Afterward, the doctor can look for ulcers, lesions, or inflammations. These may be present in Crohn’s disease or ulcerative colitis.

To pinpoint the exact cause and rule out other issues, your doctor may recommend additional tests, such as:

  • Colonoscopy: This allows the doctor to inspect the entire colon for signs of inflammation, bleeding, or other abnormalities.
  • Sigmoidoscopy: Focused on the rectum and lower part of the large intestine, this test helps identify localized issues.
  • Anoscopy: A rigid tube is used to examine the anal canal and lower rectum, which can be helpful if bleeding originates from these areas.
  • Stool culture: A sample of your stool may be tested to detect bacterial infections that can mimic or contribute to IBD symptoms.

These diagnostic methods help your healthcare provider determine the specific cause of your symptoms and guide the most effective treatment plan.

Proctitis

Proctitis is the medical term for inflammation of the lining of the rectum. This inflammation can lead to symptoms like bleeding, discomfort, and sometimes bloody diarrhea. Proctitis can develop as a result of inflammatory bowel disease, certain infections (including sexually transmitted infections or foodborne illnesses), or even after radiation therapy to the pelvic area.

In some cases, proctitis appears alongside other digestive issues, making it hard to distinguish from conditions like Crohn’s disease or ulcerative colitis without further testing. If you notice rectal bleeding or changes in your bowel habits, it’s important to consult your doctor to identify the exact cause and determine the most effective treatment.

3. Diverticular Disease 

It is a condition where a small pouch of the intestinal wall becomes inflamed and develops a sack. It can become so enlarged that it bulges through the intestinal wall. The result is blood in the stool. The cause of this condition is unknown, but it can be associated with food allergies. 

Lifestyle Tips to Help Prevent Flares

While experts still aren’t fully sure why conditions like diverticulitis or IBD show up in the first place, there are steps you can take at home to manage symptoms and lower the chances of flares.

Some helpful habits include:

  • Don’t smoke. Smoking is linked to worsening symptoms for many digestive issues.
  • Stay active. Regular exercise can help keep your digestive system healthy.
  • Drink enough fluids. Aim for enough water each day to stay hydrated and keep things moving smoothly.
  • Prioritize rest. Getting enough sleep is essential for your body to heal and manage stress, which can help keep flare-ups at bay.
  • Keep a food journal. Tracking what you eat may help identify foods that trigger your symptoms.
  • Maintain your doctor’s schedule. Regular checkups and necessary screenings can catch issues early.
  • Follow your treatment plan. Take medications as prescribed and stay up to date with any vaccinations your doctor recommends.

Making small changes to your daily routine—and working closely with your healthcare team—can make a big difference in managing these conditions over the long term.

4. Hemorrhoids (Piles)

Hemorrhoids are swollen veins in the lower rectum. Bleeding from hemorrhoids can occur for several reasons. The most common causes of bleeding are constipation and lack of exercise. Bleeding can also be caused by taking certain medications or straining while having a bowel movement.

Hemorrhoids vs. Anal Fissures: Telling the Difference

One way to distinguish between blood from hemorrhoids and blood from an anal fissure is by paying attention to pain. Bleeding from hemorrhoids typically is not accompanied by significant pain, though you might notice some discomfort or itching. In contrast, anal fissures—small tears in the lining of the anus—often cause sharp or intense pain during or after a bowel movement, in addition to bleeding.

If you notice bright red blood on toilet paper or in the bowl paired with a noticeable, lingering pain, an anal fissure is more likely the culprit. Meanwhile, painless bleeding points more often to hemorrhoids. If you’re unsure or symptoms persist, it’s always best to consult a healthcare provider.

5. Gastroenteritis

Gastroenteritis is an infection of the intestines. If you have gastroenteritis, you may have bloody diarrhea or blood in your stools. This infection usually occurs due to a virus or bacteria and usually lasts for a few days. If you have gastroenteritis, it is vital to get treated as soon as possible.

6. Food Poisoning 

Food poisoning is one of the most common causes of diarrhea. This condition can be caused by consuming contaminated food or drinking contaminated water. In most cases, it is not dangerous. However, some cases can be severe. 

Food poisoning can lead to dehydration, and it can also lead to other severe conditions, such as bacterial meningitis, which is an infection of the brain and spinal cord.  The main complications of diarrhea caused by food poisoning are dehydration and the loss of important electrolytes. In extreme cases, this can escalate to serious health risks, including seizures, brain damage, or even death if not properly managed.

Symptoms of food poisoning usually develop within 6–24 hours after eating contaminated food and can include diarrhea, nausea, stomach cramps, vomiting, and headache.

Food poisoning usually occurs within 6-24 hours of eating the food. Symptoms include diarrhea, nausea, stomach cramps, vomiting, and headache.

Preventing Bloody Diarrhea: Practical Steps

Most cases of bloody diarrhea can be prevented by keeping your digestive system healthy and reducing risk factors for common causes like infections, hemorrhoids, and inflammation.

Here are some effective steps you can take:

  • Stay Hydrated: Drink plenty of fluids each day to help keep stools soft and prevent constipation, one of the factors contributing to hemorrhoids and anal fissures.
  • Add Fiber to Your Diet: Regularly eating fiber-rich foods—such as fruits, vegetables, beans, and whole grains—can support healthy digestion and make bowel movements easier.
  • Practice Good Hygiene: Wash your hands thoroughly before eating and after using the restroom. Proper handwashing helps prevent bacterial and viral infections (like salmonella and norovirus) that may lead to bloody diarrhea.
  • Prepare Food Safely: Cook meats thoroughly and avoid consuming unpasteurized dairy or raw eggs. Be cautious with street food or undercooked dishes, and always wash fruits and vegetables.
  • Avoid Straining During Bowel Movements: Try not to spend extended periods on the toilet, and don’t force a bowel movement if one isn’t coming naturally. Consider using a footstool to put your body in a more natural position.
  • Exercise Regularly: Gentle physical activity stimulates healthy bowel movements, which can help prevent constipation and complications like hemorrhoids or diverticular disease.
  • Limit Alcohol and Quit Smoking: Both smoking and excessive alcohol intake can irritate the digestive tract and increase the risk of bowel disease.
  • Monitor and Manage Chronic Conditions: If you have a history of IBD, diverticulitis, or colon issues, follow your doctor’s recommendations, keep up with regular checkups, and take medications as prescribed.
  • Keep a Food Diary: For people with digestive issues or food sensitivities, tracking what you eat and how your body responds may help you pinpoint trouble triggers.

Although it’s not always possible to prevent every instance—especially when it comes to conditions like IBD or diverticulitis—adopting these habits can lower your risk or help you catch problems early.

Colorectal Cancer

Colorectal cancer is another possible cause of bloody diarrhea. This type of cancer develops in the colon or rectum and can result in blood appearing in your stool. The bleeding may make your stool look dark brown, almost black, or you might notice bright red blood, especially on toilet paper after wiping.

When tumors form in the colon or rectum, they can bleed intermittently. Over time, this bleeding can become more noticeable, either mixed in with your stool or as a change in its color. If you experience persistent changes in your bowel habits—such as ongoing diarrhea with blood, unexplained weight loss, or fatigue—it is important to talk to your doctor. Early detection is key to effectively treating colorectal cancer.

Treatment of Blood in Diarrhea

Sometimes diarrhea is the body’s way of getting rid of an unwanted virus. The doctors may advise a person to let diarrhea pass on its own instead of prescribing a medication that would slow the intestines.

If diarrhea persists for a prolonged period, however, additional medication and fluids may be needed, as well as medications to reduce bowel cramping. If the exact cause of dysentery is not known, a person may receive antibiotics and amoebicidal medications.

Treatment for blood in diarrhea also depends on the underlying cause. For example:

  • Hemorrhoids or Anal Fissures: Stool softeners or fiber supplements may be recommended to reduce straining and further irritation.
  • Colorectal Cancer: Treatment may involve chemotherapy, radiation therapy, or surgery, depending on the diagnosis and severity.
  • Bacterial Infections: Specific antibiotics may be prescribed if a bacterial infection is identified.
  • Dehydration: Oral rehydration solutions or intravenous fluids can help restore lost fluids and electrolytes.

In all cases, it’s important to address both the symptoms and the root cause to ensure proper recovery and prevent complications.

Preventing Colorectal Cancer

While some risk factors for colorectal cancer, such as age and family history, are beyond your control, there are steps you can take to reduce your risk:

  • Avoid smoking or try to quit if you currently smoke.
  • Limit alcohol intake as much as possible.
  • Eat a balanced diet rich in fruits, vegetables, and whole grains, while cutting back on animal fats and processed meats that contain nitrates.
  • Maintain a healthy weight with regular physical activity—aim for at least 30 minutes of movement most days of the week.
  • Regular exercise not only helps with weight but can also support your digestive health overall.

By adopting these lifestyle habits, you can play an active role in lowering your chances of developing colorectal cancer.

When To See a Doctor 

A person should also see a doctor if they have the following symptoms in addition to red diarrhea:

  • Chills
  • Diarrhea lasting more than two days
  • Weakness or fainting 
  • Over 101°F fever
  • Vomiting
  • Increasing pain or cramping

It is not normal to see blood in your stool more than a few times. If you see more than a few streaks of blood, contact your doctor. Those who feel lightheaded, cannot eat or drink, or experience severe abdominal pain should also seek medical attention.

Blood in diarrhea is a condition that several reasons can cause. The onset of blood in the stool may vary based on the cause and the patient’s history.