Hi - silly me - I read your posting too quickly and noticed that you DID state your age. Sorry about that.
Maybe, prior to your colonoscopy and the discussion with your specialist, it may be informative to type in "rectal bleeding" to google or yahoo so that you can get an idea of possible underlying causes.
All the best
Morecambe
Hi - there are numerous causes of blood in stools. They range from the serious type (at worst rectal cancer) to more minor causes such as an anal fissure or haemhorroids.
You don't state your age - the more serious causes tend to occur at the age of 40+ .
My suggestion is that you ask your doctor "what is going through your mind in deciding that I need a colonoscopy. What is the worst and what are the other options?" A colonoscopy is a very comprehensive test and will uncover everything.
Good luck
Morecambe