tea wise you can have an tea that is made of the leaf , so normal tea , green tea , mint etc but nothing citrus or made from fruit or berries . You can have the odd coke zero , Dr pepper zero , asda diet coke or sainsburys diet coke but water is the best . I use dulcolax pico perles whch my local tesco sells , they are great to have just incase you get bunged up and are gentle so no stomach cramps . Movicol is great at keeping you regular and preventing you getting bunged up or some people find psyllium husks work wonders ( holland and barrat sell them i believe ) hope that helps