Rectal Bleeding: Causes, Red Flags and When to See a Specialist

Bleeding from the back passage is common and usually has a harmless cause — but because it can occasionally be the first sign of something serious, it should never simply be ignored.

Common causes

The most frequent causes are haemorrhoids (piles) and anal fissures, both of which typically produce bright red blood. Other causes include inflammation of the bowel lining, polyps, infections and, less often, bowel cancer.

Red flags that need prompt assessment

See a doctor without delay if bleeding comes with any of the following:

• a persistent change in bowel habit (looser, more frequent, or constipated)
• blood mixed in with the stool, or dark/tarry stools
• unexplained weight loss or tiredness
• a family history of bowel cancer, or you're over 50
• abdominal pain or a feeling of incomplete emptying

These don't mean you have cancer, but they do mean the cause should be established properly rather than assumed.

Why "it's probably just piles" isn't enough

Piles are common, so it's tempting to attribute any bleeding to them. The risk is that a more serious cause is missed because the symptoms overlap. A specialist assessment — and, where indicated, a colonoscopy — confirms the diagnosis rather than guessing it.

When to seek urgent help

Heavy bleeding, feeling faint, or bleeding with severe pain warrants urgent medical attention.

This article provides general information and is not a substitute for individual medical advice. Please consult a qualified clinician about your own circumstances.