I have travelled quite a lot to different countries in Asia. Never had a problem with the food, but in Delhi the infamous Delhi belly hit me. I am cautious with the food but not hysterical about it.

For me it took exactly 7 days and medicine did not help. It stopped as suddenly as it started (started on the plane back home - yuk). My doctor told me, that it is not worse than any of the small 24 hour diarrhoes that you can catch at home, too, but because our system is not used to it, it will just take longer. So I had to sit and wait....

Let me add one hint to the ones above: avoid water melons, because sometimes those are said to be made heavier by injection of (bad tap) water.

Anyway, I hope you enjoy your trip!

Cheers,
Torsten