How did diarrhea kill so many people before and now it’s not that big of a deal?

Question

Title really, is it just that our diet is better and decent food is much more abundant or is it just general hygiene?

In: 36

Answer 1

Sunset found her squatting in the grass, groaning. Every stool was looser than the one before, and smelled fouler. By the time the moon came up, she was shitting brown water. The more she drank the more she shat, but the more she shat, the thirstier she grew.
George R.R. Martin