No, my dear, it is not a good idea. Although I am not a gastrointerologist, I know that they don t like vitamins taken one week before the procedure, the day before they want you to avoid all dyes like purple, blue, red. With cayenne pepper I can just see it adding a red color that shouldn t be there and it might cause some mild irritation that also shouldn t be there. For one day, just stick to plain stuff that doesnt have a red color to it unless it is in whatever they give you to drink prior to the colonoscopy. It is also not good to become a chemist and add things to the bowel prep - then you are changing how the chemicals act with each other and on you. I do not advise putting anything into the prep solutions and not to stain your colon the day before the procedure. Kind Regards, Kathryn Shattler,MS,RDN, Dietitian