I have tested different variants of viagra, cialis and other brands. I have took it over a period of 3 years at different time. And recently, discovered blood in my stool the day after I take it. It started to be very small blood mixed with stool, red color, and yesterday I tried after 2 months without any viagra, and got heavy bleeding. Already took an appointment for a coloscopy, but meanwhile I would like to see if this problem have been seen by any other patient and the causes/risks.