Hi. I understand your concerns. I just had my endoscopy and colonoscopy at the same time. Now, trust me....I am the biggest baby when it comes to medical procedures. I survived and it really truly wasn't bad at all. I was so scared, I was on the floor and wouldn't get dressed and tried to let my husband sleep so that we would be too late to get to the appt. But, my kids woke up and the rest is history. I was afraid of the prep causing terrible cramps, nausea etc. I was afraid of the terrible gas afterwards and more problems. It was nothing like I expected. I had the easier prep because I convinced my dr. I would not drink that gallon of stuff. They gave me the Dulcolax prep. No problem...no cramps. Then I was out for both procedures. Endoscopy is a tube down your throat. Colonoscopy is the tube up through the colon. I told dr. how uneasy I was so he made sure I was out. I fell asleep and just woke up and it was over. I've had no gas pain and no diarrhea or pains since. I was very lucky. Just be very honest with your physician and make sure he is kind! We are the "boss" of our bodies and no one can "make" us do things against our will. Good luck to you....if I can do it, anybody can!