Common causes of bleeding from the anus include constipation, anal fissures, and hemorrhoids. A small tear in your anus (anal fissure) bleeding with or without lumps, itching or pain sexually transmitted infections (stis) like genital warts, damage from anal sex bright red blood without pain side effect of blood-thinning medicine like warfarin or aspirin, broken blood vessels in the gut (angiodysplasia). The bleeding may result in bright red blood in the stool as well as maroon colored or black stool. The bleeding also may be occult (not visible with the human eye). The common causes of rectal bleeding from the colon include anal fissure, hemorrhoids, diverticulosis, colon cancer and polyps, colonic polyp removal, angiodysplasias. While bleeding from the rectum or anus can be surprising and uncomfortable, it usually indicates a minor issue, like an anal fissure (tear) or hemorrhoids. Anal fissures fissures are tearing and bleeding of the rectal or anal tissue 8. Hemorrhoids these are swollen veins either inside the rectum or beneath the outer skin of the anus 9. These enlarged veins can bleed easily under additional pressure, such as when you are having a bowel movement. Anal fissures (tears in the tissue inside your anus) medical conditions, such as cancer, colitis,. Your rectal bleeding stopped for a time, but has started again. Anal herpes is caused by the sexually transmitted herpes simplex virus. Learn how to tell if you have anal herpes and what treatments are available. Have someone drive you to an emergency room if rectal bleeding is continuous or heavy accompanied by severe abdominal pain or cramping schedule a doctors visit. Make an appointment to see your doctor if you have rectal bleeding that lasts more than a day or two, or earlier if the bleeding worries you. Anal cancer, cancer located at the end of the large intestine, has symptoms that include anal or rectal bleeding, anal pain or pressure, anal discharge or itching, a change in bowel movements, andor a lump in the anal region.