Causes of rectal bleeding can range from mild to serious. Conditions associated with rectal bleeding include:
Anal fissures. Small tears in the lining of the anus can lead to bleeding and pain when passing stools. Tears can occur because of constipation or during childbirth.
Angiodysplasia. Enlarged blood vessels develop in the intestine. They can become fragile, break, and bleed.
Hemorrhoids. Also called piles, these are masses of tissue made up of blood vessels and muscle fibers. Internal hemorrhoids are inside the body. They don’t hurt but can cause bleeding. In some cases, they can pass through the anus.
Constipation. Hard stool and straining to relieve constipation can lead to anal fissures and hemorrhoids, both of which can result in bleeding.
Anal or colorectal polyps. Polyps are growths that can appear in many places throughout the body. If polyps develop in the intestine, they can bleed. Polyps aren’t cancerous, but some can become malignant in time.
Ulcers. An ulcer can form when an erosion worsens in the digestive track. Black, tarry stools may occur if an ulcer is bleeding higher in the gut, but an ulcer further down may produce bright red blood. However, this isn’t always the case, and your doctor will need to investigate.
Anal cancer or colon cancer. As tumors form, they need blood vessels to grow. The blood vessels in the colon are fragile and can tear, causing bleeding. Only 3.4 percentTrusted Source of cases of rectal bleeding are due to colon cancer.
Inflammatory bowel disease (IBD). This includes ulcerative colitis (UC) and Crohn’s disease. Bleeding may occur alongside rectal pain and diarrhea.
Diverticular disease. Diverticula are small pouches or bulges in the colon where, over time, blood vessels can erode, rupture, and bleed. When there are no symptoms, it’s called diverticulosis, but if inflammation occurs, this is diverticulitis. Together, they’re called diverticular disease.
Infections. Intestinal infection, or infections caused by bacteria, such as salmonella, can cause bleeding.
Bleeding conditions. Some conditions can contribute to bleeding because they affect the blood’s ability to coagulate. They include vitamin K deficiency, hemophilia, and a low platelet count, also called thrombocytopenia.
Damage to the upper gastrointestinal (GI) tract. Tears or other problems in the stomach or even the esophagus can cause bleeding from the rectum. Bleeding from the upper GI tract is more likely to appear as black, tarry stools.