There are some other alternatives too.

I recall once a young boy who had a kidney transplant who couldn't take regular laxatives for some reason. His grandmother gave him a tablespoonful of extra virgin olive oil... and it worked!
She claimed it never fails!

Another thing is sorbitol. This sweetener is found in dietetic candies. You have to read the labels. But it is also in chewing gum and over use of that will loosen people up. My son had that reaction on 1/2 roll of PEZ sugar free. And it was even on an episode of House once! I had a reaction to Cherry Cordial kisses by Hershey...they now have sorbitol in them. So that would be one way to get your chocolate and also your laxative! heheheheheh.