It might be a bit of an Australianism.
Basically a euphemism for food poisoning (originally through contaminated water in Bali).
Discussion
Why would you try it ? 😂
Sensitive Australian stomaches not used to the unsterilised local water supply.
Sometimes it happens from the water used in cooking/cleaning.
Sometimes it's just regular food poisoning. Sometimes it's just an excuse to drink more cold beer (it's hot over there).
It's kinda part of the experience 🤷