Bloody diarrhea refers to loose stools mixed with blood, which may appear bright red, dark red, or tar-like. This condition can signal a range of issues, from minor anal injuries to serious gastrointestinal diseases. While diarrhea itself is common, the presence of blood warrants medical attention to identify the underlying cause and provide appropriate treatment.

What Blood in Diarrhea Looks Like

appearance of blood
Blood in diarrhea may show up in various ways:

  • On the surface of stool

  • In the toilet bowl

  • Only on toilet paper after wiping

The color offers clues about its source. Bright red blood typically suggests bleeding from the lower colon or rectum, such as from hemorrhoids. Dark red or tarry stools may indicate bleeding from higher up in the digestive tract, potentially pointing to more serious issues.

Common Causes

anal fissures
These are small tears in the skin around the anus, often caused by straining or chronic diarrhea. They can produce sharp pain during bowel movements and leave bright red blood on the tissue or in the toilet.

hemorrhoids
Swollen veins in the rectum or anus may bleed during bowel movements, leading to small amounts of bright red blood. Hemorrhoids can also cause itching, discomfort, or a feeling of incomplete evacuation.

infections
Infectious colitis, food poisoning, or sexually transmitted infections like gonorrhea or chlamydia can inflame the colon or rectum, resulting in bloody diarrhea. Diverticulitis—inflamed pouches in the colon—can also cause significant bleeding.

inflammatory conditions
Ulcerative colitis and Crohn’s disease are forms of inflammatory bowel disease (IBD) that damage the lining of the digestive tract. Proctitis, or inflammation of the rectum, may also lead to bleeding. This condition can stem from infections, STIs, or radiation therapy.

ulcers
Peptic ulcers in the stomach or small intestine can erode blood vessels, causing bleeding. This blood turns stools dark or tar-like in appearance.

colorectal cancer
Tumors in the colon or rectum may bleed, with signs including dark stool or visible red blood. Because the cancer consumes nutrients and damages tissues, bleeding may occur as the tumor progresses.

Causes in Children

In children, the most common cause of bloody diarrhea is constipation, which can lead to anal fissures or hemorrhoids. Other possible causes include infections, IBD, peptic ulcers, or congenital issues like Meckel diverticulum.

Diagnosis

Healthcare providers will begin by asking about medical history and symptoms. A physical exam may be followed by tests, such as:

  • Anoscopy: views the anal canal and rectum

  • Colonoscopy: inspects the entire colon

  • Stool culture: checks for infection-causing germs

  • Sigmoidoscopy: examines the lower part of the colon

Treatments

hydration
Fluids are vital, especially with ongoing diarrhea. Drinking electrolyte-rich drinks or diluted juices helps prevent dehydration. In severe cases, intravenous (IV) fluids may be necessary.

targeted treatments
The specific cause guides treatment:

  • Stool softeners for fissures or hemorrhoids

  • Antibiotics for bacterial infections

  • Chemotherapy, radiation, or surgery for colorectal cancer

severe bleeding
Blood transfusions may be required if rectal bleeding is extensive.

Prevention

general strategies

  • Avoid straining during bowel movements

  • Stay hydrated

  • Eat a high-fiber diet

  • Practice safe sex and proper hygiene

  • Use laxatives responsibly

for IBD

  • Quit smoking

  • Maintain a healthy sleep schedule

  • Track symptom triggers via a food diary

  • Take prescribed medications

  • Stay current with vaccinations

for colorectal cancer

  • Reduce red and processed meat intake

  • Avoid smoking and limit alcohol

  • Eat more fiber, fruits, and vegetables

  • Maintain a healthy weight and exercise regularly

  • Ask a doctor about aspirin use for prevention

Complications

The major risks from bloody diarrhea include dehydration and electrolyte imbalance. If left untreated, these complications can cause seizures, brain damage, or even death.

A Quick Review

Blood in diarrhea is a symptom that may arise from several conditions, including hemorrhoids, infections, inflammatory diseases, ulcers, or cancer. While many causes are treatable, medical evaluation is important to determine the exact reason. Staying hydrated and managing the underlying issue can lead to a full recovery.