The quickest thing is a Fleet's enema or a warm water enema which can be found at any drug store. That will work in about 5 minutes. A Fleet's enema will probably work better but it is more painful. A warm water enema is just putting some warm water in an enema bottle which isn't as painful but might not work as well.
thank you very much for the comment...i actually drank just a bit of magnesium citrate and it worked...i had considered an enema..but phamacist said it could linger into the next day..and i had to get on airplane at 6 am..