I'd just like to add that having too much vitamin C in one hit will or at least should give you the shits. You'd probably need at least 4 or 5 grams to get this effect.

I recently bought what seemed incredibly cheap vitamin C (in 1000mg tabs). I gave it the shits test and even 10 grams did not have the desired effect. I concluded that the actual dose of vitamin C in each tablet was clearly nowhere near as much as it should have been.

So be warned. Cheap isn't necessarily good value.