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Is bright red blood in stool serious?

Seeing blood in your stool can be alarming, but not all causes are serious. The color of the blood provides clues about the location of bleeding in your digestive tract. Bright red blood typically indicates bleeding low in the colon or rectum, which is often from hemorrhoids or anal fissures. However, bright red blood can sometimes result from more serious conditions like colon cancer or inflammatory bowel disease. Let’s take a closer look at the possible causes and when to see your doctor.

What causes bright red blood in stool?

Here are some common causes of bright red blood in or on the surface of stool:

  • Hemorrhoids – Swollen veins in the anus and lower rectum that can bleed, itch, and cause pain.
  • Anal fissures – Small tears in the thin, moist tissue lining of the anus.
  • Diverticulosis – Small pouches called diverticula can form in the colon wall and become inflamed or bleed.
  • Angiodysplasia – Abnormal blood vessels in the colon that can bleed.
  • Colitis – Inflammation of the colon from infections, ischemia, or inflammatory bowel diseases.
  • Colon polyps – Growths that form on the inner wall of the colon and can bleed.
  • Colon cancer – Cancerous tumors in the colon or rectum that can bleed.

Bright red blood typically originates from the lower colon or rectum, also called the distal colon. Bleeding higher up in the digestive tract, such as from stomach ulcers, often appears darker or altered because digestive juices change the color and composition of blood.

What do hemorrhoids look like?

Hemorrhoids are a common source of minor rectal bleeding. Here are some characteristics of hemorrhoids:

  • Swollen, inflamed veins around the anus or lower rectum.
  • Can be internal (inside the anus) or external (under the skin around the anus).
  • May bulge out from the anus and need to be pushed back in.
  • Can bleed, often seen as bright red blood on toilet paper or in the stool.
  • May cause anal itching, discomfort, and pain.

Hemorrhoid bleeding is typically mild and intermittent, such as a few drops after a bowel movement. Bleeding from hemorrhoids is rarely severe unless they become thrombosed or necrotic.

What causes anal fissures?

Anal fissures are small tears or splits in the thin moist tissue lining the anus. Common causes include:

  • Constipation – Hard, dry stools can stretch and tear anal tissue.
  • Severe diarrhea – Loose, watery stools can irritate and erode anal tissue.
  • Childbirth trauma
  • Anal sex
  • Medical procedures like colonoscopy

Anal fissures cause sharp anal pain and spasm. They may bleed a small amount during bowel movements, often seen as bright red blood on the surface of stool or toilet paper.

What are the symptoms of colitis?

Colitis refers to inflammation of the colon. Symptoms depend on the cause but may include:

  • Diarrhea – Loose, frequent stools that may contain blood and mucus.
  • Abdominal pain and cramping
  • Bloating and gas
  • Urgency to have a bowel movement
  • Inability to pass stool (constipation)
  • Fatigue and malaise
  • Fever, in some cases

Bleeding can vary from mild to severe depending on the level of colon inflammation. Colitis requires treatment of the underlying cause.

What do colon polyps look like?

Colonic polyps are abnormal growths that arise from the lining of the colon. Features include:

  • Can be flat, raised, or pedunculated (on a stalk)
  • Often small, less than 1 cm
  • May bleed periodically, causing passing of bright red blood
  • Can become cancerous so removal is recommended

All polyps should be removed during colonoscopy. Larger or more numerous polyps may indicate colon cancer risk.

Colon cancer warning signs

Colorectal cancer can cause rectal bleeding. Additional key warning signs include:

  • Bleeding from rectum or blood in/on stool
  • Change in bowel habits – constipation, diarrhea
  • Abdominal pain or cramping
  • Weakness and fatigue
  • Unexplained weight loss

While most colon bleeding is from benign sources, any significant or persistent bleeding warrants medical evaluation. Catching colon cancer early greatly improves survival.

When to see a doctor

Consult your doctor if you experience:

  • Bleeding that is persistent, frequent, or increasing
  • Bright red blood that coats or mixes with the stool
  • Bleeding accompanied by abdominal pain, chills, or weight loss
  • Anal pain that persists longer than 1-2 weeks
  • Changes in bowel habits lasting more than a few weeks

While a small amount of blood from hemorrhoids or a tear is usually normal, significant bleeding or symptoms that persist require evaluation. Your doctor can examine the rectum and perform tests like a fecal occult blood test or colonoscopy to determine the bleeding source.

Medical treatments

Treatment options for rectal bleeding depend on the cause:

Condition Treatments
Hemorrhoids Over-the-counter creams, ointments, or suppositories. Sitz baths. Improving constipation. Procedures to remove clotted hemorrhoids. Surgery for severe cases.
Anal Fissures Stool softeners. Sitz baths. Topical medications. Surgery if fissure persists.
Colitis Antibiotics, anti-inflammatory, or immunosuppressant medications specific to the cause of colitis.
Polyps Endoscopic polyp removal (polypectomy) during colonoscopy.
Colon Cancer Surgery, chemotherapy, radiation, and targeted therapy.

Most rectal bleeding can be treated effectively with simple at-home care, medications, or minor procedures. Your doctor will determine if colonoscopy or referral to a gastroenterologist is needed for evaluation and management.


You can reduce your risk of many common causes of rectal bleeding by:

  • Eating more fiber – Fruits, vegetables, whole grains to avoid constipation.
  • Staying hydrated – Drink plenty of fluids.
  • Avoiding prolonged straining – Don’t delay when feeling urge to have bowel movement.
  • Avoiding irritating foods – Spicy, greasy, and processed foods.
  • Being gentle – Use soft toilet paper and wet wipes.
  • Practicing anal hygiene – Wash carefully after bowel movements.
  • Treating diarrhea or constipation promptly.
  • Getting screened – Colonoscopy starting at age 45 to find polyps or early cancer.

Making dietary modifications to have soft, regular stools and good anal hygiene can prevent recurrent issues with hemorrhoids and anal fissures. Colonoscopy screening aims to find precancerous polyps before they become cancerous.

When to seek emergency care

Seek emergency medical care if you have:

  • Large amounts of bloody stool
  • Lightheadedness or dizziness
  • Rapid heart rate
  • Fainting
  • Abdominal swelling
  • High fever
  • Uncontrolled bleeding

These signs can indicate significant blood loss or a severe abdominal condition. Prompt medical treatment is needed to identify and stop the bleeding source as well as to replace lost blood volume.

Takeaway points

  • Bright red blood in or on stool typically originates from the lower colon or rectum.
  • Common causes are hemorrhoids, anal tears, diverticula, angiodysplasia, colitis, polyps, and cancer.
  • Hemorrhoids and anal fissures are common sources of minor rectal bleeding.
  • Significant, persistent, or frequent bleeding should be medically evaluated.
  • Treatments range from over-the-counter remedies to procedures or surgery.
  • Good anal hygiene, fiber intake, and screening colonoscopy can prevent many causes.
  • Seek emergency care for heavy bleeding, dizziness, weakness, high fever, or abdominal swelling.

While alarming, bright red blood in stool or on toilet paper is rarely from a serious cause. Minor bleeding typically resolves with at-home treatments. Persistent or worsening bleeding should prompt medical evaluation to determine the colon or rectal source. Proper prevention and screening are key to reducing rectal bleeding risk.