Hi. Thanks for your query. Noted the history you having constipation and only Sodium picosulfate works. Colonoscopy clean- normal, intermittent inability to empty rectum without assistance as by intravaginal pressure or contact by enema, a known IBS-C. Wants to know what to ask to the Gastroenterologist. - You have to ask for the following: What type of IBS is this. Which medicine to be tried and to be continued and for how much length. Are there any studies to decide the exact problem. Role of anxiety and/ or stress or any other psychological condition that can instigate or enhance the problems. What are the foods and beverages that you have noticed to cause the constipation. The answers to these will help one to get the proper diagnosis and the treatment is successful only after the basic causes are tackled with.