Anal fissure
This is a small painful tear in the skin of the anus that causes discomfort due to the sensitivity of the skin. You can experience bright red blood per rectum. It increases the feeling of wanting to pass stool even if the bowels are empty.
Hemorrhoids (piles)
These are swollen blood vessels in and around the rectum. When you are having a bowel movement, these swollen vessels bleed leaving streaks of red blood in your stool and on the toilet paper. Poor dietary fiber and fluid intake are contributory.
Colorectal cancer and polyps
Colon cancer is a silent killer. Symptoms occur in advanced stages and the bleeding is usually occult and found only on specialized stool testing. If diagnosed at an early stage it is curable. It starts with small growths called polyps and early detection and removal can help treat and stop the spread of colon cancer.
Angiodysplasia
This is a case where the blood vessels in the colon enlarge causing painless bleeding. It is more common among senior people.
Diverticula
Pockets or dimples that develop in the wall of the colon and can present with sudden, painless rectal bleeding.
Other uncommon causes of rectal bleeding include reverse reaction of anticoagulant drugs, inflammatory bowel diseases such as Crohn's disease and Ulcerative Colitis. Also, brisk upper gastrointestinal bleeding (stomach and intestine), such as from an ulcer, can produce rectal bleeding.