Don't eat epsom salt.
If you're ever so severely clogged up that you're approaching a week without - Epsom salt will, in fact, work. It works so well that I'd recommend pre/probiotic foods for a couple days afterward. It completely cleans you out.
Otherwise, I agree. You have to know why you're clogged, too; if you got no clue, go see a Dr.
It can also be added to your bathwater or used as a foot soak.