When should you see a doctor about blood in stool?

Bright red blood may come from the anus or lower bowel, including an anal fissure, while darker blood or black, tarry stool can indicate bleeding higher in the digestive tract. Infection, inflammatory bowel disease such as Crohn's disease or ulcerative colitis, polyps, and cancers are other possibilities. Blood does not identify the cause by itself.

Note the colour, amount, frequency, pain, bowel changes, fever, and medicines such as blood thinners. Do not dismiss bleeding because it is painless or appears once. A clinician may examine the area and decide whether stool tests, blood tests, or further bowel assessment are needed.

Seek emergency care for heavy or continuous bleeding, black tarry stool, faintness, confusion, severe abdominal pain, repeated vomiting, or marked weakness. Arrange prompt medical assessment for any unexplained recurrence, blood mixed through stool, new constipation or diarrhoea, or unintended weight loss.

Ask where the bleeding may be coming from, which medicines could worsen it, whether you need tests, and what symptoms should prompt immediate reassessment.