Reasons for rectal bleeding

Bright-red blood on toilet paper or on the outside of stool can come from the anus or lower rectum, including irritation after hard stools. Blood mixed through stool, dark stool, mucus, diarrhoea, cramps, or a change in bowel habit can indicate bleeding farther inside the bowel. Gastroenteritis may cause bleeding with diarrhoea and abdominal discomfort.

Crohn's disease and ulcerative colitis can inflame the bowel and cause bleeding with urgency or loose stools. Diverticular disease, polyps, bowel cancer, rectal cancer, and gastrointestinal stromal tumour are other conditions a clinician may consider. Rectal bleeding is a symptom, not a diagnosis, so its appearance does not identify the cause by itself.

Record the colour and amount of blood, whether it is on paper or mixed with stool, and any pain, diarrhoea, constipation, weight change, or tiredness. Arrange a medical review even if bleeding is painless or stops, especially when it recurs or bowel habits have changed. A clinician may examine the area and decide whether stool tests, blood tests, or a bowel examination are appropriate.

Seek emergency help for heavy or continuous bleeding, black tar-like stool, dizziness, fainting, confusion, severe abdominal pain, or a fast heartbeat. Obtain prompt medical assessment for bleeding with fever, repeated diarrhoea, worsening pain, persistent change in bowel habit, unexplained tiredness, or unintentional weight loss.

Ask where the bleeding may be coming from, whether your medicines could contribute, which tests are suitable, and whether a polyp removal procedure or specialist review may be needed.