Rectal bleeding (bleeding from the bottom) may be caused by a swollen blood vessel or a small tear around the anus, but it can have a more serious cause and should never be ignored.
Don't let embarrassment stop you seeing your doctor. You should always get rectal bleeding checked to rule out more serious causes.
Most people with rectal bleeding will see small amounts of bright-red blood on the toilet paper after they have been to the toilet, or a few droplets that turn the water in the toilet pink. These are typical signs of piles (haemorrhoids) or a small tear (anal fissure) in the skin of your anus, the opening through which stools pass.
Both of these are very common problems, but you should not assume they are the cause of your rectal bleeding. You should still see a doctor if you have these symptoms.
In general, bright-red blood means the bleeding has come from somewhere near your anus.
If the blood is darker in colour and sticky, the bleeding may have occurred higher up your digestive system. This type of bleeding can turn your faeces black or plum-coloured (known as melaena).
Having plum-coloured, dark and sticky faeces may be a medical emergency – you should see your doctor immediately or contact NHS 111.
Is it bowel cancer?
Many people with rectal bleeding worry they may have bowel cancer. While rectal bleeding can be a sign of early-stage bowel cancer, other factors may also be present for your doctor to think you're at risk.
You should be urgently referred to a specialist with suspected bowel cancer if you have rectal bleeding and:
- you are aged 40 or older and have passed looser or more frequent stools for the last six weeks
- you are aged 60 or older and the bleeding has lasted for six weeks or more
- your doctor has found an abnormality (such as a lump) after examining you
- you also have anaemia, a reduced number of red blood cells
- you have a family history of bowel cancer
- you have ulcerative colitis
Find out more about bowel cancer and read the NICE guidelines for being referred with suspected bowel cancer (PDF, 806Kb)
Common causes of rectal bleeding
Some of the most common causes of visible rectal bleeding in adults are outlined below. However, do not try to diagnose yourself, and always see your doctor for a proper diagnosis.
Click on the links for more information about these causes.
Piles are swollen blood vessels in and around the rectum. They can bleed when you have a bowel movement, which can leave streaks of bright-red blood in your stools and on the toilet paper. Piles may also cause itchiness around your anus. They often heal on their own.
An anal fissure is a small tear in the skin of the anus, which can be painful as the skin is very sensitive. The blood is usually bright red and the bleeding soon stops. You may feel like you need to keep passing stools, even when your bowel is empty. It often heals on its own within a few weeks.
An anal fistula is a small channel that develops between the end of the bowel, known as the anal canal or back passage, and the skin near the anus (the opening where waste leaves the body). They are usually painful and can cause bleeding when you go to the toilet.
Angiodysplasia is a condition in which the blood vessels in the colon (part of the large bowel) become enlarged. It is more common in older people and can cause painless rectal bleeding.
Gastroenteritis is a viral or bacterial infection of the stomach and bowel, which your immune system will usually fight off after a few days. It can cause diarrhoea that contains traces of blood and mucus, as well as other symptoms such as vomiting and stomach cramps.
Diverticula is where small bulges form in the lining of your lower bowel. These contain weakened blood vessels that can burst and cause sudden, painless bleeding (you may pass quite a lot of blood in your stools).
Colon cancer and polyps
Colon cancer (a type of bowel cancer) is a common cancer and the reason why you should always get checked by your doctor if you have rectal bleeding. The only symptom may be rectal bleeding in the early stages, so don't ignore it. Colon cancer can be more easily treated if diagnosed at an early stage.
Colon cancer starts as little growths called polyps, removing these early can prevent the cancer taking hold.
Cancer of the rectum
Cancer of the rectum is a type of bowel cancer that usually affects older people, but can only be ruled out after seeing your doctor.
Less common causes of rectal bleeding
Some of the more unusual causes of rectal bleeding include:
- Anticoagulant drugs, such as warfarin or aspirin, which are taken to reduce your chance of a blood clot but can sometimes cause internal bleeding.
- Inflammatory bowel disease, such as Crohn’s disease or ulcerative colitis. These long-term conditions cause the lining of the bowel to become inflamed. Crohn’s disease affects the gut higher up, whereas ulcerative colitis affects the large bowel and rectum, further down. Both tend to cause bloody diarrhoea.
Lester and his wife Carolyn talk about his experience of bowel cancer, and offer their advice to others.