Rectal bleeding (hematochezia) refers to the passage of bright red blood from the anus. Rectal bleeding may be moderate to severe and most bleeding comes from the colon, rectum, or anus. Common causes include anal fissures, hemorrhoids, diverticulitis, and more.
Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.
Rectal bleeding is the passage of blood through the
Rectal bleeding may be red, maroon, black or occult.
The common causes of rectal bleeding include anal
fissure, hemorrhoids, diverticulosis, colon cancer and polyps, post-polypectomy,
angiodysplasias, colitis and proctitis, and Meckel's diverticula. Rectal
bleeding also may be seen with bleeding that is coming from the stomach,
duodenum, or small intestine.
The origin of rectal bleeding is determined by history and physical examination, anoscopy, flexible sigmoidoscopy,
colonoscopy, radionuclide scans, visceral angiograms, and blood tests.
Rectal bleeding is treated by correcting the low blood volume and
anemia, determining the site and cause of the bleeding, stopping the bleeding, and
What does rectal bleeding (blood in stool) mean?
Rectal bleeding (known medically as hematochezia) refers to the passage of red blood from the anus, often
mixed with stool and/or
blood clots. (It is
called rectal bleeding because the rectum lies immediately above the anus, and although
red blood in the stool indeed may be coming from the rectum, as discussed later,
it also may be coming from other parts of the gastrointestinal tract.) The
severity of rectal bleeding (i.e., the quantity of blood that is passed) varies widely.
Most blood in the stool or rectal bleeding are mild and stop on their own. Many patients report only passing a few drops of fresh blood that turns
the toilet water pink or observing spots of blood on the tissue paper. Others may
report brief passage of a spoonful or two of blood. Generally, mild rectal
bleeding can be evaluated and treated in the doctor's office without
hospitalization or the need for urgent diagnosis and treatment.
Bleeding also may be moderate or severe. Patients with moderate
bleeding will repeatedly pass larger quantities of bright or dark red
often mixed with stools and/or blood clots. Patients with severe bleeding may pass several
bowel movements or a single bowel movement containing a large amount of blood.
Moderate or severe rectal bleeding can quickly deplete a patient's body of
blood, leading to symptoms of weakness, dizziness, near-fainting or fainting, and
low blood pressure or orthostatic hypotension (a drop in blood pressure
when going from the sitting or lying position to the standing position). Rarely,
the bleeding may be so severe as to cause shock from the loss of blood.
or severe rectal bleeding usually is evaluated and treated in the hospital. Patients
with signs and symptoms of reduced volume of blood often require emergency
hospitalization, and transfusion of blood.