What does unexplained weight loss feel like with bowel cancer?

Bowel cancer can affect digestion and the movement of stool through the bowel. You may notice a change from your usual bowel pattern, such as looser stools, constipation, urgency, narrower stools, or alternating bowel habits. Cramping, bloating, reduced appetite, or feeling full can make eating harder. Bleeding from the bowel may lead to tiredness and reduced stamina. Some people have few symptoms at first. These signs can also arise from non-cancer conditions, so their presence does not establish a diagnosis.

Arrange a medical appointment for ongoing unplanned weight loss or a bowel change that does not settle. Describe when it began, how your bowel pattern has changed, whether you have seen blood or dark stool, and whether pain or eating difficulties are present. Bring a list of medicines and relevant family history. A clinician may recommend examination, blood tests, stool assessment, or further bowel investigations. Keep drinking fluids and choose foods you tolerate while waiting for advice; do not use repeated laxatives or anti-diarrhoeal medicines without guidance.

Seek urgent assessment for heavy or repeated rectal bleeding, black tarry stool, severe or increasing abdominal pain, a swollen abdomen with vomiting, inability to pass stool or gas, fainting, or marked weakness. Contact a clinician promptly if weight loss is continuing alongside persistent bowel changes, worsening tiredness, or difficulty keeping food and fluids down.

Could the weight loss and bowel changes have a shared cause? Which symptoms make testing more urgent? What information should I record about stool, pain, appetite, and hydration? Which investigations might be considered? What should I do if bleeding, vomiting, or abdominal swelling appears?