Blood in Stool: Causes, Diagnosis, and Treatment

Blood in stool means you can see blood when you have a bowel movement. It might appear as red streaks on toilet paper or turn your stool black and tarry. Sometimes it comes from minor issues like hemorrhoids, but other times it needs medical attention. If you see blood, don't ignore it — talk with a healthcare provider to find out why.

In plain words

Blood in stool means you see blood when you go to the bathroom. It might look bright red or make your stool black and tarry. Sometimes it comes from minor issues like hemorrhoids, but other times it needs medical attention. If you see blood, talk with a healthcare provider to find out why.

What is Blood in Stool: Causes, Diagnosis, and Treatment?

Blood in stool means you can see blood when you have a bowel movement. It might appear as red streaks on toilet paper or turn your stool black and tarry. Sometimes it comes from minor issues like hemorrhoids, but other times it needs medical attention. If you see blood, don't ignore it — talk with a healthcare provider to find out why.

Symptoms

Early symptoms

  • Early signs of blood in stool: Early symptoms vary depending on the underlying cause. See a doctor for evaluation if you notice unusual changes. (1) (2)

Serious or emergency symptoms

  • Large amounts of blood in stool: If you see a lot of blood in your stool or it looks black and tarry, this could mean bleeding higher up in your digestive system. This type of bleeding requires prompt medical attention. Seek same-day medical care if you pass large amounts of bright red blood or black, tarry stools. (2) (5)
  • Blood with dizziness or fainting: If you feel lightheaded, dizzy, or faint along with seeing blood in your stool, this could indicate significant blood loss and requires urgent medical attention. Go to the emergency room or call for emergency help if you feel faint or dizzy with bloody stools. (5)
  • Pain or swelling in abdomen: If you have severe stomach pain, swelling, or tenderness along with bloody stools, this could indicate a serious condition such as inflammatory bowel disease flare or intestinal obstruction. Seek immediate medical attention for severe abdominal pain with bloody stools. (7)
  • Unexplained weight loss with bloody stools: If you're losing weight without trying and also noticing blood in your stool, this combination of symptoms needs prompt medical evaluation as it could indicate a serious condition. See a doctor within a week if you have unexplained weight loss along with blood in your stool. (1)

Causes

Primary causes

  • Hemorrhoids (piles): Swollen veins in your rectum or anus can bleed, especially during bowel movements. You might see bright red blood on toilet paper or in the toilet bowl. This is often painless. (3) (6)
  • Anal fissure: A small tear in the lining of the anus can cause bright red bleeding, usually noticed on toilet paper. These often hurt during and after bowel movements. (4)
  • Inflammatory bowel disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause bloody diarrhea along with abdominal pain. The blood might be mixed in with stool rather than just on the surface. (7)
  • Colorectal polyps or cancer: While less common than other causes, blood in stool can sometimes indicate growths in the colon or rectum. This is why it's important to get checked, especially if you're over 45 or have a family history. (1) (9)

Risk factors

Individual risk factors for blood in stool vary by medical history

Risk factors depend on the underlying cause. Discuss your personal risk with your doctor. (1) (2)

Diagnosis

Doctors use several methods to find the cause of blood in stool. They'll ask about your symptoms, examine you (which might include checking your rectum), and possibly order tests. Common tests include stool sample analysis, colonoscopy, or flexible sigmoidoscopy. The right tests for you depend on your symptoms, age, and medical history. Always let your doctor know if you notice blood in your stool so they can recommend the appropriate evaluation for your situation.

Treatment

Medication options

Lifestyle and self-care

  • Increase fiber and fluids for hemorrhoids: Eating more high-fiber foods (like fruits, vegetables, and whole grains) and drinking plenty of water can soften stools to help prevent hemorrhoid flare-ups that cause bleeding. (6)

Always discuss dosing and treatment changes with your own prescriber.

When to see a doctor

Routine follow-up

  • Make an appointment to see your doctor if you notice blood in your stool, even if it's just a small amount or happens only once. It's especially important if you're over 45 or have a family history of colon cancer. (2) (9)

Seek emergency care

  • Seek emergency care or call your local emergency number if you have large amounts of blood in your stool, black/tarry stools, or if you feel faint, dizzy, or have severe abdominal pain with bloody stools. (5) (8)

Frequently asked questions

What causes Blood in Stool?

Common causes include hemorrhoids (swollen veins in the rectum), anal fissures (small tears), and less commonly, issues like inflammatory bowel disease or polyps. The color and amount of blood can help indicate where the bleeding is coming from. Your doctor can help determine the specific cause in your case. (3) (4) (6)

When should I worry about Blood in Stool?

See a doctor right away if you have large amounts of blood, black/tarry stools, dizziness, fainting, or severe pain with bloody stools. Also seek medical attention if the bleeding continues, gets worse, or happens frequently, or if you have other symptoms like weight loss. It's better to get checked than to wait and worry. (2) (5) (1)

Is Blood in Stool serious?

Sometimes it is serious, but often it's from minor issues like hemorrhoids. The only way to know is to get checked by a doctor. Even if the cause isn't serious, finding and treating it early is important. Don't assume it's nothing just because it doesn't hurt or goes away temporarily. (2) (5)

How do I get rid of Blood in Stool?

Treatment depends on the cause. For hemorrhoids and fissures, increased fiber, stool softeners, and warm baths may help. For other causes, your doctor will recommend specific treatments. Never try to treat unexplained blood in stool on your own — always consult a healthcare professional first to determine the right approach for your situation. (6)

When should I see a doctor about Blood in Stool?

Make an appointment if you see any blood in your stool, even if it's just once. Seek same-day care for large amounts of blood, black/tarry stools, or if you feel dizzy. If you're over 45 or have risk factors for colon cancer, don't delay getting checked when blood appears. (2) (5) (9)

References

  1. CDC — Colorectal Cancer: What Are the Symptoms? source 1
  2. NHS — Blood in Stool source 2
  3. NHS — Piles (Haemorrhoids) source 3
  4. NHS — Anal Fissure source 4
  5. MedlinePlus — Bloody or Tarry Stools source 5
  6. MedlinePlus — Hemorrhoids source 6
  7. MedlinePlus — Inflammatory Bowel Disease source 7
  8. Mayo Clinic — Blood in Stool source 8
  9. AGA — Colorectal Cancer Guidelines source 9