Loss of appetite and a change in bowel habits

Appetite may fall during infection, stress, medication use or digestive upset. Constipation, diarrhoea or narrower stools can follow diet changes, dehydration, inflammation or altered bowel movement. Bowel cancer and rectal cancer can also present with appetite loss and changed bowel habits, but these symptoms do not identify the cause by themselves.

Write down when the change began, stool frequency and appearance, appetite, abdominal discomfort, medicines and any blood or mucus. Drink fluids unless a clinician has restricted them, and avoid starting repeated laxatives or anti-diarrhoeal medicines without advice if symptoms are new or severe. Arrange a clinical review if the pattern persists or keeps returning.

Seek urgent help for heavy rectal bleeding, black stools, severe or worsening abdominal pain, repeated vomiting, a swollen abdomen with inability to pass stool or gas, fainting or confusion. Contact a clinician promptly for blood mixed with stools, persistent change, increasing tiredness or ongoing weight loss.

Could my medicines or diet explain this pattern? Do I need an examination or bowel tests? What should I do if constipation alternates with diarrhoea? Which bleeding or pain symptoms need same-day help?