Rectal bleeding (bleeding from the bottom) is often noticed as small amounts of bright-red blood on toilet paper or a few droplets that turn the water in the toilet pink.
In general, bright-red blood means the bleeding has come from somewhere near your anus and is a typical sign of piles (haemorrhoids) or a small tear (anal fissure) in the skin of your anus.
Although these are common problems, don't let embarrassment stop you seeing your GP. You should always get rectal bleeding checked to rule out more serious causes. Around 10% of adults experience rectal bleeding every year in the UK.
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 GP immediately or contact NHS 111.
How your GP investigates rectal bleeding
If your GP needs to examine you to find out what's causing your rectal bleeding, they may carry out a rectal examination. This involves putting a gloved finger inside your bottom (rectum).
There's no need to feel embarrassed or nervous: it's a quick and painless procedure that GPs are used to doing.
The examination usually takes one to five minutes, depending on whether your GP finds anything unusual.
You may be referred to a hospital or specialist clinic if further examinations and tests are needed.
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're aged 40 or older and have passed looser or more frequent stools for the last six weeks
- you're aged 60 or older and the bleeding has lasted for six weeks or more
- your GP 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
Bowel cancer is sometimes called colon or rectal cancer, depending on where the cancer starts.
Find out more about bowel cancer, and read the NICE guidelines for being referred with suspected cancer.
Common causes of rectal bleeding
Some of the most common causes of visible rectal bleeding in adults are outlined below. However, don't try to diagnose yourself, and always see your GP for a proper diagnosis.
Click on the links for more information about these causes.
- piles (haemorrhoids) ‐ 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.
- anal fissure ‐ 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.
- anal fistula‐ 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're usually painful and can cause bleeding when you go to the toilet.
- angiodysplasia ‐ abnormal blood vessels in the gastrointestinal tract, which can cause bleeding. It's more common in older people and can cause painless rectal bleeding.
- gastroenteritis ‐ a viral or bacterial infection of the stomach and bowel, which your immune system usually fights off after a few days. It can cause diarrhoea containing traces of blood and mucus, as well as vomiting and stomach cramps.
- diverticula ‐ small bulges 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).
- bowel cancer (colon or rectal cancer) ‐ you should always get checked by your GP if you have rectal bleeding. The only symptom of bowel cancer may be rectal bleeding in the early stages, so don't ignore it. Bowel cancer can be treated more easily if it's diagnosed at an early stage.
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.
- bowel polyps ‐ small growths on the inner lining of the colon or rectum. These are common and often don't cause symptoms, but may lead to a small amount of blood in your stool.
- sexually transmitted infections (STIs) ‐ any sexual activity involving the anal area can spread STIs, which may sometimes lead to rectal bleeding. Read more about the risks of anal sex.
