Juddy said..
Depending on how strong your stomach is, it may also be worth taking some lomotil on a daily basis - regardless of whether you need it or not - just to minimise any potential for bali belly or similar.
Definitely do NOT take lomotil until you actually have the runs.
I don't like the stuff at all until you really, really need it.
Lomotil binds you stomache up to stop you sh!ting.
It does not somehow purify what you eat or drink.
What you want is what your body is doing for you, that is eliminating as much of the bug as quickly as it can from your body.
Why on earth would you take something that retains the toxins in your body??
If you get the runs it's better to starve the bug.
Make sure you drink plenty of water to replace the fluids you are eliminating.
Then after a couple of days ease back onto foods that don't keep the bug alive in your stomach.
Fatty foods, meats etc are out.
Plain foods like white boiled rice, bread are OK.