Healthy Living

Most Common Causes of Blood in the Stool

Most Common Causes of Blood in the Stool

Causes of Gastrointestinal Tract and Rectal Bleeding

Hemorrhoids (Piles)

Hemorrhoids are probably the most common cause of blood in the stool. These are swellings in the lower rectum (lower back passage) and anus. Inside the lining of the lower rectum and anus is a group of small blood vessels known as veins. These veins swell and are filled with extra blood, thus, the development of hemorrhoids.

Many people can develop hemorrhoids at some point in their life. Hemorrhoids are extremely common. Hemorrhoids may be small or develop together. Most of the time, small hemorrhoids are painless. On the other hand, large hemorrhoids can cause pain, itchiness, irritation, and some mucous discharge.


Diverticula are small pouches that are seen on the wall of the intestines. One small pouch is called a diverticulum. Diverticula may develop in any region of the intestines, but they usually develop in the colon. It may cause some bleeding, and this will pass an amount of blood through the anus. Bleeding is the result of the burst of blood vessels that occurs in the walls of the colon. The bleeding is typically painless and abrupt, but it could be heavy. Changes in bowel movements and abdominal pains are other symptoms of diverticula.

Anal fissure

Anal fissure is a condition where there is a small tear on the skin of the anus. The tear is usually small, less than a centimeter, but it can cause pain since the anus is a very sensitive body part. People with anal fissure notice blood in their stool. The blood is bright red in color and may stain the tissue.

Ulcerative colitis

Ulcerative colitis is a condition where the colon and rectum are inflamed. Bleeding may occur as a result of the ulcers that developed in the wall of the inflamed colon or rectum. A common symptom of ulcerative colitis is bloody diarrhea.

Other forms of colitis are inflammation of the colon and proctitis. Proctitis is the inflammation of the rectum that can also cause rectal bleeding.

Crohn's disease

Crohn’s disease is an illness that results in a gut inflammation. It flares up from time to time. The symptoms and its severity usually depend on which part of the gut is affected. The common symptoms of Crohn’s disease include abdominal pain, feeling unwell, and bloody diarrhea.


Rectal bleeding is one of the common symptoms of colon and rectum cancers. Older people are usually affected by these types of cancer. Bleeding may not be observed until the later stages of the condition. Other symptoms of colon and rectal cancers include weight loss, constipation, diarrhea, and fatigability due to anemia.


Angiodysplasia is a disease where a number of blood vessels in the inner lining if the colon becomes enlarged. It could develop to any parts of the colon, but it is very common in the ascending colon. The cause of angiodysplaisa is not known, but it is usually seen in older people. Rectal bleeding caused by angiodysplasia is typically painless. The blood may be bright red or the stool may be black in color. Angiodysplasia may also result to non-visible blood loss.


Polyps in the colon are small growths in the lining of the colon or rectum. The polyps are usually benign or non-cancerous, which may cause no problems. However, a polyp may sometimes bleed and can become cancerous. Older people are usually affected by colon polyps.

Stomach and Duodenal ulcers

Stomach and duodenal ulcers may cause some bleeding and could result in black or plum-colored stools.

Gut infections

Gut infections may result to bloody diarrhea because of the inflammation of the gut. Infections that invaded the gut make it possible for the presence of blood in the stool.