Bloody Stool

Overview

Bloody stool means there is blood in or on a bowel movement, on the toilet paper, or in the toilet bowl. The blood can look bright red, dark red, or maroon, or the stool can be black and tarry. The color often hints at where the bleeding is coming from: bright red blood usually comes from the lower digestive tract, such as the rectum or anus, while black, tarry stool often comes from higher up, such as the stomach.

Many causes of blood in the stool are minor and easily treated, such as hemorrhoids or a small tear at the anus. However, bloody stool can also be a sign of infection, inflammation, or a more serious condition, so it should never be ignored. Heavy bleeding, black tarry stools, or bleeding with dizziness or weakness can indicate significant blood loss and needs urgent care.

Common Causes

Bloody stool can come from anywhere along the digestive tract. Common causes include:

• Hemorrhoids: swollen veins around the anus, a very common cause of bright red blood.
• Anal fissures: small tears at the anus, often with pain during bowel movements.
• Infections: certain gut infections causing bloody diarrhea. See gastroenteritis.
• Inflammatory bowel disease: such as IBD.
• Peptic ulcers: bleeding from the stomach causing black, tarry stools. See peptic ulcer.
• Polyps and other growths: which can bleed, and warrant evaluation, especially with age.

Associated Symptoms

Blood in the stool may appear with other symptoms that suggest the cause:

• Rectal pain or itching, common with hemorrhoids and fissures
• Diarrhea or constipation
• Abdominal pain or cramps
• Black, tarry stools (melena) from upper-gut bleeding
• Fatigue or pale skin from anemia with ongoing bleeding
• Unintended weight loss or a change in bowel habits

Bloody stool with dizziness, fainting, heavy bleeding, or black tarry stools is a warning sign of significant blood loss and needs emergency care.

Diagnosis & Evaluation

A clinician evaluates bloody stool to find the source and rule out serious causes. Evaluation may include:

• History: the color and amount of blood, pain, bowel habits, and other symptoms.
• Physical exam: including an examination of the anus and rectum.
• Stool tests: for infection and hidden (occult) blood.
• Blood tests: to check for anemia from blood loss.
• Endoscopy: colonoscopy or upper endoscopy to view the digestive tract directly and take biopsies.

Treatment & Management

Treatment depends on the cause and the amount of bleeding:

• Hemorrhoids and fissures: high-fiber diet, fluids, stool softeners, and topical treatments; minor procedures if needed.
• Treating infections: supportive care and, when appropriate, specific treatment for the infection.
• Managing inflammation: medications for inflammatory bowel disease.
• Treating ulcers: acid-reducing medicines and addressing the cause of a peptic ulcer.
• Removing polyps: during colonoscopy when found.
• Urgent care for heavy bleeding: fluids, blood transfusion if needed, and procedures to stop active bleeding.

Self-Care & Prevention

Some causes of bloody stool can be prevented or made less likely with good bowel habits:

• Eat plenty of fiber and drink enough fluids to keep stools soft and prevent constipation, which contributes to hemorrhoids and fissures.
• Avoid straining and prolonged sitting on the toilet.
• Stay physically active to support healthy bowel function.
• Limit alcohol and avoid overuse of NSAID painkillers, which can irritate the stomach and cause bleeding.
• Handle and store food safely to reduce gut infections.
• Keep up recommended colorectal cancer screening, such as colonoscopy, especially from middle age onward.

Most importantly, never ignore blood in the stool; even when minor causes are likely, having it checked ensures more serious conditions are not missed.

When to See a Doctor

See a doctor for any blood in the stool, even if it seems minor, so the cause can be identified. Seek emergency care right away if you have:

• Large amounts of blood or continuous bleeding
• Black, tarry stools or vomiting blood
• Dizziness, fainting, a rapid pulse, or weakness
• Severe abdominal pain or a rigid abdomen

Heavy bleeding or black tarry stools with faintness can indicate significant internal blood loss and needs immediate medical care. Persistent or recurrent bleeding, a change in bowel habits, or weight loss also need prompt evaluation.

Related Topics

Frequently Asked Questions

References

1. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Gastrointestinal Bleeding.
2. Mayo Clinic. Rectal bleeding — Causes.
3. MedlinePlus, U.S. National Library of Medicine. Bloody or tarry stools.
4. American College of Gastroenterology. Rectal Bleeding.