Actually there is no harm in having a colonscopy.It is not at all any dangerous procedure.It will help doctors to find out the reason of bleeding apart from that any other abnormality in colon like polyps,Diverculosis etc. I myself had colonscopy though in my case it was poly removal .I had the same type of feeling before the procedure.But when I decided to have the procedure and after the procedure I made the right decision to scope one of the important part of my anatomy.Think about it and feel free to email me for any additional questions.