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Bright Red Blood in Stool

Edmund has spent the last ten years working in clinical research. He has written many articles on human anatomy and physiology.

Causes of blood in poop

Causes of blood in poop

Blood in Stool

Bright red blood in stool is alarming because it points to bleeding in the gut. However, not all red stools are caused by bleeding. The color can also come from certain foods.

Foods Associated With Red Stool

In the quest to reduce cost and increase profit, synthetic food colorants have become much more popular than natural colorants. Unfortunately, our digestive enzymes can't completely break down some of these artificial dyes. After consumption, a large portion of a red dye could be excreted intact, retaining its red color—staining your stool blood red.

Medical Conditions Associated With Bright Red Blood in Stool

Hematochezia is the medical term for bright red blood in the stool. Rectorrhagia is when only blood is present without any bowel movement. Bleeding can occur anywhere in the gastrointestinal (GI) tract—this includes the mouth, esophagus, stomach, and small and large bowel.

Blood traveling through the gut turns black as it gets broken down by digestive juices. The farther away the bleeding is from the anus, the more likely blood from it will be broken down before excretion. A dark or black stool suggests bleeding higher up the GI tract.

On the other hand, bright red blood in stool suggests bleeding in the lower part of the GI tract. The bleed, in this case, is closer to the anus. This does not leave sufficient time for blood to be broken down by digestive juices. Hence, the red maroon color of blood can be seen in pieces of stool in the toilet bowl or on the toilet paper. There are various conditions associated with GI bleeding; some of the common ones are mentioned below.

  • Anal fissures are tears in the lining of the anal canal. People with anal fissures are typically presented with sharp tearing pain and bleeding, often during defecation. The pain may last minutes to hours after defecation and can progress to burning and itching. Anal fissures commonly occur when a dry constipated stool scratches the wall of the anal canal. They sometimes heal on their own without any real medication.
  • Diverticulosis is a condition associated with the formation of small pouches in the lining of the colon. Doctors believe that blood vessels in these pouches may weaken and rupture, causing bloody stools. Even though not proven, doctors say that people on low fibre diets are more prone to develop diverticulosis. Some symptoms of diverticulosis are linked to significant loss of blood. These include fatigue, shortness of breath and light-headedness.
  • Ulcerative colitis is a disease that causes severe inflammation of the mucosa of the colon. According to researchers, some individuals are genetically predisposed to developing ulcerative colitis. Factors that can trigger the disease include microbes, autoimmune reactions, and food allergies. The inflammatory process begins primarily in the rectum and can spread to other parts of the colon as the disease progresses. It can cause significant bleeding when it erodes down to blood vessels. Other symptoms are fever, diarrhea, fatigue and abdominal pain.
  • Arterio-venous malformation (AVM) is an abnormal collection of blood vessels that can bleed intermittently. The bleeding is mainly because AVM-arteries connect directly to AVM-veins without passing through capillaries. The small size of capillaries reduces pressure as blood moves through to veins. Veins have thin walls and are generally not meant to withstand high pressures. AVM veins can easily rupture, causing bleeding.
  • Hemorrhoids or Piles are swollen, inflamed veins inside or around the anus. They mainly result from the exertion of too much pressure on the anal region. This is common during pregnancy, constipation, prolonged sitting, heavy weightlifting or obesity. Rectal bleeding occurs when the delicate surface of the hemorrhoid is damaged—mainly from strain or irritation. Additional symptoms are rectorrhagia, redness, itching, rectal pain, and discomfort.
  • Colon cancer is cancer that starts in the colon. It is often discussed together with rectal cancer hence also referred to as colorectal cancer. Regular screening is recommended for high-risk individuals in order to catch cancer before it develops. It is highly curable when diagnosed at an early stage. Key symptoms that suggest colon cancer include fatigue, anemia, weight loss, diarrhea, constipation, bloating and other changes in bowel habits. However, doctors have reported cases of colon cancer with no symptoms.

Bleeding From the Upper GI Tract

Hemoglobin is the part of a red blood cell that contains iron. Unlike bleeding in the lower GI tract, blood from upper GI bleeding has enough time to interact with digestive juices. Iron in hemoglobin is oxidized as it passes through the gut. This results in a black, tarry stool known as melena.

Melena is worrisome because it indicates active bleeding from the upper gut. The color of blood in stool is a good indicator of the source of the bleeding. Medical causes of melena include:

  • Peptic ulcer: sore in the upper part of the small intestine.
  • Esophagitis: inflammation of the esophagus.
  • Gastritis: inflammation of the stomach lining.
  • Esophageal varices: abnormally enlarged veins in the esophagus.
  • Gastric varices: abnormally enlarged veins in the stomach.
  • Mallory-Weiss syndrome: tear in the mucous membrane at the stomach and the esophagus.

Fecal Occult Blood Test (FOBT)

It takes a significant amount of blood to be able to visually detect bleeding in one’s stool. If GI bleeding drops below a certain threshold, blood in the stool may no longer be visible.

FOBT is a test performed to detect small amounts of blood in stool, quantities smaller than can be detected by the naked eye.

There are several different methods to do the FOBT test. One method involves the following steps:

  • A small amount of fresh fecal sample is collected and smeared onto a small test card.
  • The card is then sent to the lab.
  • A special solution is added to the smear.
  • The smear should turn blue in the presence of blood.

Talk About It!

There is a stigma surrounding bowel disorders. Sufferers of bowel disorders are often embarrassed to talk about their bowel habits. Bright red blood in stool is a red flag but does not always point to a disease. However, it may be caused by a simpler condition such as anal fissures or a potentially life-threatening condition such as colorectal cancer.

Generally, blood in your stool must prompt you to take a trip to your doctor to make sure it is not associated with a serious condition. A large amount of bleeding (including melena) can be life-threatening. In this case, you should seek urgent medical attention.


This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.


Jegrossart on November 25, 2016:

beware of Nestle, Nesquik Strawberry Syrup. I was ready to take my son to the emergency room last night. I even called the Kaiser nurse and after my explanation she said "yes, please take him to be seen as soon as possible" As we were leaving I asked again to tell me all hed eaten. He said he felt fine. Finally he remembers putting Nesquik Strawberry Syrup on a slice of pumpkin pie. I squirted a few Tablespoons into the toilet and the color matched the picture i had taken to share with the doctor. Scared the heck out of me thinking so much blood was in his stool. Thankly just syrup passing through him. I am tossing the rest. Creepy stuff.