Signs & symptoms

Colorectal cancer might not cause symptoms right away, but if it does, it may cause one or more of these symptoms:

• A change in bowel habits, such as diarrhea, constipation, or narrowing of the stool, that lasts for more than a few days
• A feeling that you need to have a bowel movement that's not relieved by having one
• Rectal bleeding with bright red blood
• Blood in the stool, which may make the stool look dark
• Cramping or abdominal (belly) pain
• Weakness and fatigue
• Unintended weight loss

If you have any of these symptoms you should contact your GP for advice.