Yesterday I drunk tap water in Ho Chi Minh. I knew it is unsafe to drink it, but only after I gulped down a cup of water did I notice it was tap water. Since it is safe in my country, I just drunk it unconsciously...
I believe that it won't get you into anything serious in most chances. But in general, is there anything you should/could do after recognizing to gulp down tap water in a country where it is unsafe? For example should I change what to eat for a while or should I not eat anything, etc...?