Diseases & Conditions

Blood in the Stools

Overview, Causes, & Risk Factors

Blood in the stools means that blood from somewhere in the body is being excreted in the stool, or bowel movement.

What is going on in the body?

Blood in the stools can occur for many reasons. It can range from a small amount of blood, as in blood-streaked stools, to large amounts of blood, with bright red blood throughout the stool. Blood in the stools may come from anywhere in the body, but the source is usually the gastrointestinal tract. The gastrointestinal tract includes the esophagus, stomach, small intestine, and large intestine.

What are the causes and risks of the symptom?

Blood in the stools can be caused by many conditions. These include:

  • hemorrhoids, which are masses of small, dilated veins in or near the anus
  • peptic ulcer, which is an open sore or lesion in the lining of the stomach or small intestine
  • colorectal cancer
  • food poisoning
  • heavy metal poisoning, such as lead poisoning
  • esophageal varices, which are twisted, dilated veins that can cause pain and bleeding in the esophagus
  • colorectal polyps, which are tumors in the bowel that may be noncancerous or cancerous
  • Crohn's disease, which can cause inflammation in any part of the gastrointestinal tract
  • diverticulitis, a condition that causes pockets in the intestine, which can become inflamed and infected
  • anal fissure, which is a tear in the lining of the anus
  • anorectal fistula, which is a crack in the lining of the anus that extends to the muscle of the anus
  • ulcerative colitis, a disease that can cause swelling and sores in the lining of the colon
  • bleeding disorders
  • abdominal injuries, such as crush injuries from a car accident or a fall
  • a foreign body in the colon or rectum
  • alcohol abuse
  • dysentery or other intestinal disorders, such as Meckel's diverticulum or intussusception
  • ulcerative proctitis, which is an inflammation of the rectum and anus
  • certain tests or procedures, such as a colonoscopy or polypectomy. During a colonoscopy, the healthcare provider uses a flexible tube with a camera on the end to view the lining of the large intestines. A polypectomy is the removal of a colorectal polyp, or growth, from the intestinal lining.

  • Symptoms & Signs

    What other signs and symptoms are associated with this symptom?

    When someone has blood in the stools, more information will be needed. The healthcare provider may ask:

  • When was the blood in the stools noticed?
  • Do the stools have streaks of blood only on the outside, or is there blood throughout the stool?
  • Is the blood bright red or dark?
  • How long has there been blood in the stools?
  • Have the stools been consistently bloody, or does the blood come and go?
  • Is there any abdominal distress or abdominal distention?
  • Is there any vomiting, diarrhea, or constipation?
  • Is there any weakness, dizziness, or fainting?
  • Is there any fatigue or weight loss?
  • Is there any chest pain or shortness of breath?
  • Has there been any injury to the abdomen?
  • Is there any history of peptic ulcers, cancer, heart disease, or lung disease?
  • Is the person taking any medications?

  • Diagnosis & Tests

    How is the symptom diagnosed?

    A thorough medical history and physical examination is the first step in determining the cause of blood in the stools. Blood tests, such as a complete blood cell count, or CBC, can evaluate the effect of the blood loss.

    Stool tests, such as a fecal occult blood test, may be done. A recent study has shown that a screening for fecal occult blood every 1 to 2 years can significantly reduce the incidence of colorectal cancer. A positive test for blood in the stools often detects precancerous lesions that can be removed before colorectal cancer develops.

    Scans, endoscopy, an upper GI series, and a barium enema may be used to examine the inside of the stomach and intestines. Ultrasound and rectal exams may also be done.

    Prevention & Expectations

    What can be done to prevent the symptom?

    Careful management of disorders like Crohn's disease or ulcerative colitis may prevent blood in the stools. Careful monitoring and treatment of hemorrhoids also may prevent blood in the stool. Avoiding excess alcohol may decrease this risk. Some causes of blood in the stool cannot be prevented, but prompt treatment may make rectal bleeding less likely.

    What are the long-term effects of the symptom?

    Long-term effects of blood in the stools depend on the underlying cause. If the cause is an anal fissure or hemorrhoids, treatment may stop the bleeding. Bleeding caused by diverticulitis may improve when the diverticulitis is treated with diet, antibiotics, or surgery. If the underlying cause of the bloody stools is colorectal cancer, permanent damage to the intestine may occur, or the cancer may be fatal.

    What are the risks to others?

    Blood in the stools is not contagious.

    Treatment & Monitoring

    What are the treatments for the symptom?

    Treatment of blood in the stools depends on the underlying cause. In an emergency situation, intravenous fluids are given to replace fluids lost from bleeding or dehydration. Blood pressure, heart rate, temperature, and breathing rate are watched for signs of shock.

    If the bleeding is caused by a condition that can be treated with antibiotics or antifungal medications, the bleeding may stop on its own. Diet may help with some conditions, such as diverticulitis.

    Surgery is needed in some cases of blood in the stools. Surgery may be used to repair the problem or remove a cancerous area. Radiation therapy and chemotherapy may also be used to treat cancer.

    What are the side effects of the treatments?

    All medications have possible side effects. Antibiotics can cause stomach upset and allergic reactions. Surgery poses a risk of infection, bleeding, or allergic reaction to anesthesia. Chemotherapy can have many side effects, such as stomach upset, hair loss, and weakness.

    What happens after treatment for the symptom?

    In many cases, no further measures are needed following treatment. The person is considered cured and can return to normal activities. In other cases, the cause is not curable and needs further treatment. Some causes of bleeding, such as colorectal cancer, may result in death.

    How is the symptom monitored?

    Underlying diseases, such as ulcerative colitis, may require lifelong medical treatment and monitoring. Any new or worsening symptoms should be reported to the healthcare provider.


    Author:Eileen McLaughlin, RN, BSN
    Date Written:
    Editor:Ballenberg, Sally, BS
    Edit Date:12/31/00
    Reviewer:Barbara Mallari, RN, BSN, PHN
    Date Reviewed:07/05/01


    Professional Guide to Signs and Symptoms, Springhouse, 1997

    Current Medical Diagnosis and Treatment, 39th ed., Tierney, 2000