Rectal bleeding means blood that comes out through the anus. You might see bright red streaks on the toilet paper, drops in the toilet bowl, blood mixed into the stool, or stool that is dark or black. It is one of the most common reasons people see a GI doctor. Often the cause is something simple, like hemorrhoids or a small tear. But the same signs can come from polyps, inflammation or cancer, so the cause deserves to be found, not guessed. Dr. Pimienta sees adults from across Los Angeles County for rectal bleeding, in English or Spanish.
Call 911 or go to the nearest emergency room if you are passing a large amount of blood or clots, feel dizzy, faint, short of breath or have a racing heart, have black, tarry stools, are vomiting blood, or have severe or worsening abdominal pain. Heavy bleeding can become dangerous quickly, especially if you take a blood thinner.
What does the color of the blood mean?
The color gives a clue about where the blood comes from, though it is not a diagnosis on its own.
| What you see | Where it often comes from |
|---|---|
| Bright red blood on the paper or in the bowl | Near the end of the bowel: the anus, rectum or lower colon |
| Dark red or maroon blood, or blood mixed into the stool | Higher up in the colon, or sometimes the small intestine |
| Black, sticky, tar-like stool (melena) | Usually the stomach or upper small intestine. Needs urgent care. |
Some things change stool color without any bleeding. Iron pills and bismuth (the pink stomach medicine) can turn stool dark or black, and beets or red food coloring can look like blood. If you are not sure, it is safer to get checked.
What causes rectal bleeding?
These are the most common causes in adults:
- Hemorrhoids. Swollen veins in and around the anus. They often cause painless bright red blood on the paper or in the bowl, sometimes with itching or a bulge.
- Anal fissure. A small tear in the skin of the anus, usually from passing a hard stool. It causes sharp pain during and after bowel movements, with a little bright red blood. Constipation is a common trigger for both fissures and hemorrhoids.
- Diverticular bleeding. Diverticula are small pouches in the wall of the colon, common with age. A blood vessel near one can bleed suddenly, often a large amount of red or maroon blood without pain.
- Colon polyps. Growths on the lining of the colon. Larger ones can bleed. Most are not cancer, but some can become cancer if left in place. Learn more about colon polyps.
- Colitis. Inflammation of the colon, from infection, reduced blood flow (ischemic colitis) or inflammatory bowel disease. It often comes with diarrhea, urgency or cramping.
- Colorectal cancer. Less common, but one of the main reasons bleeding should be checked, since cancer found early is much easier to treat.
- Other causes, such as small abnormal blood vessels in the colon (angiodysplasia), bleeding after a polyp is removed, or past radiation to the pelvis.
Why shouldn't I just assume it is hemorrhoids?
Hemorrhoids are very common, so it is natural to blame them. The trouble is that hemorrhoids and more serious causes can look the same: bright red blood is one of the warning signs of colorectal cancer listed by the American Cancer Society. Having hemorrhoids also does not mean they are the source of the bleeding you see.
Colorectal cancer has also become more common in adults under 50, which is one reason screening now starts at 45 for people at average risk. A check is especially important if:
- You are 45 or older, or have never had a colonoscopy
- The bleeding is new for you, or different from before
- Blood is mixed into the stool rather than only on the paper
- You also have a change in bowel habits, belly pain, weight loss or tiredness
- A blood test shows low iron or anemia
- A parent, brother, sister or child had colorectal cancer or advanced polyps
When should I see a GI doctor?
Any rectal bleeding that is new, keeps coming back or does not have a clear cause is a reason to make an appointment. That includes bleeding you think is from hemorrhoids that has not been checked by a doctor. A small amount of blood once, with an obvious cause like a hard stool, may settle on its own, but if it happens again, or you are in any of the groups above, it is time for a visit. For heavy bleeding, dizziness or black stools, do not wait for an appointment: call 911 or go to the emergency room.
How does Dr. Pimienta find the cause?
Dr. Pimienta believes good care begins with listening. He will ask how the blood looks, how much there is, how often it happens, and about pain, bowel habits, weight, medicines (especially blood thinners, aspirin and anti-inflammatory pain relievers) and family history. Then:
An exam
A general exam, and with your permission a gentle exam of the anal area to look for hemorrhoids, fissures or other causes.
Blood tests
A blood count and iron levels show whether you have lost enough blood to cause anemia.
A look inside the colon
For most adults, a colonoscopy is the best way to see the whole colon and rectum. Polyps can be removed and biopsies taken during the same exam. Dr. Pimienta performs colonoscopy at Specialty Surgical Center of Beverly Hills, less than a mile from his office.
Other tests when they fit
Black stools usually call for an upper endoscopy to look at the esophagus, stomach and small intestine. Stool tests may be used when infection is possible.
Once the cause is clear, treatment follows it: fiber and stool softeners for hemorrhoids and fissures, removal of polyps, medicine for colitis, or other care as needed. Your plan depends on your health; Dr. Pimienta will talk with you about what fits you.
What can I do in the meantime?
- Keep stools soft: drink water and add fiber slowly, from food or a fiber supplement.
- Do not strain, and do not sit on the toilet for long periods (put the phone down).
- A warm sitz bath (sitting in a few inches of warm water) can ease hemorrhoid or fissure discomfort.
- Write down when bleeding happens, how much and what it looks like. A photo can help your doctor.
- Do not stop a prescribed blood thinner on your own. Call the doctor who prescribes it.
- Do not let an over-the-counter hemorrhoid cream delay a check-up if the bleeding keeps coming back.
Getting seen in Los Angeles
Dr. Pimienta sees adults at his Wilshire Boulevard office, near the Miracle Mile and Beverly Hills, and by secure video for patients in California. He accepts Medicare; other patients are seen as self-pay, and the team explains pricing before anything is booked. Send a request online or call (424) 281-7392.
Questions patients ask
Is a little blood on the toilet paper normal?
It is common, but it is not normal. A single small streak after a hard stool may be from a minor tear. If it keeps happening or you are not sure of the cause, have it checked.
Does rectal bleeding mean I have cancer?
Usually not. Most rectal bleeding comes from hemorrhoids, fissures or other benign causes. But because cancer is one possible cause, especially after 45, finding the source is important.
Do I need a colonoscopy if I am young?
Not always. It depends on your age, symptoms, family history and exam. Dr. Pimienta will explain whether a colonoscopy makes sense for you, and why.
Can a stool test check my bleeding instead?
No. Stool tests such as FIT are designed for screening people without symptoms. If you are seeing blood, you need an evaluation that finds the source, which usually means a colonoscopy.
Can medicines cause bleeding?
Blood thinners and anti-inflammatory pain relievers can make bleeding from any cause more likely or heavier. They do not explain bleeding on their own, so the source still needs to be found.
References
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Gastrointestinal (GI) Bleeding.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Hemorrhoids.
- American Cancer Society. Colorectal Cancer Signs and Symptoms.
- US Preventive Services Task Force. Colorectal Cancer: Screening. 2021.