Blood in the stool is caused by bleeding somewhere in the gastrointestinal (GI) tract. This is the organ system that ingests food, digests food, and discharges waste. Because bleeding can occur anywhere in the gastrointestinal tract, from the mouth to the anus, bloody stools may have many causes. Blood in the stool is usually blood red or brown. When it comes from the upper digestive tract, where it is digested, it will look different. This blood is called black manure and it looks black like tar.

The following are possible causes of blood in the stool:

1.     Upper gastrointestinal bleeding

Undigested blood in the stool may come from the upper gastrointestinal tract. The most common cause is that the bleeding occurs near the ligament that supports part of the duodenum, which is the first and shortest part of the small intestine.

2.     Anal fissure

Anal fissure is the most common cause of blood in the stool in babies, but it can also be obtained in adults. They are caused by constipation or large, hard stools that are difficult to pass. This may cause the skin to break. Stretch the anal skin so that the fissures are visible.

3.     Polyps

These are small growths in the lining of the intestine. There are several different types of polyps. Adenomatous polyps are some of the most common polyps. These polyps grow on the lining of the colon or large intestine. About 25% of adults over 50 have this type of polyp. Adenomatous polyps can develop into colorectal cancer or colon cancer or rectal cancer. Although adenomatous polyps cause most cases of colorectal cancer, only about 5% will become cancerous.

4.     Hemorrhoids

Hemorrhoids are inflamed blood vessels that can protrude from the anus. They look like cushions. Hemorrhoids are usually uncomfortable. They may be painful or itchy. Because there are many blood vessels around the anus and rectum, hemorrhoids will leak bright red blood.

5.     Vascular dysplasia

Unexplained bloody stools are usually caused by vascular dysplasia, which is a malformation of the intestinal blood vessels. Vascular dysplasia is common during end-stage kidney disease or kidney failure. People with a common inherited bleeding disorder called von Willebrand disease may also have vascular dysplasia.

6.     Inflammatory bowel disease (IBD)

Inflammatory bowel disease (IBD) is an autoimmune disease of the intestinal tract. When you have an autoimmune disease, your immune system attacks a part of your own body. In IBD, this can cause inflammation of the intestines. Crohn’s disease and ulcerative colitis are the two most common types of IBD.

7.     Diverticulosis

A diverticulum is an abnormal pouch that can form in the lower part of the small intestine. There are two types of diverticulosis. The simple presence of a diverticulum is called diverticulosis. However, sometimes the diverticulum becomes infected. When this occurs, the disease is called diverticulitis. Both types of diverticulosis cause pain and blood in the stool. Diverticulum is caused by weakness in the wall of the colon. Sometimes they can grow to a few inches in diameter. This disease is generally attributed to a low fiber diet, but the actual cause is still unclear.

8.     Ischemic colitis

Ischemic colitis occurs when the blood vessels supplying the large intestine become narrowed or blocked. Most cases of ischemic colitis occurs in ages people. This situation can be short-term or long-term. Most cases of ischemic colitis are short-lived and resolve on their own. However, sometimes people with severe ischemic colitis must be hospitalized. Patients with severe illness may require intravenous fluids, antibiotics and intestinal rest, or restricted diet.

There may be many reasons to having blood in the stool. Haemorrhoids (berak berdarah) and anal fissures are uncomfortable and painful, but harmless. However, some gastrointestinal bleeding may require surgical treatment, including upper gastrointestinal bleeding, polyps, vascular dysplasia, inflammatory bowel disease, diverticulosis, and ischemic colitis. Sometimes blood in the stool can be a sign of a serious illness, such as cancer. Blood in the stool may also be a false alarm.