The region is generally safe. You even don't get bothered by anyone for buying stuff or guidiance.
But there's a thread by the road traffic, 'cause the motorists drive not carefully and DUI is very common. The most dangerous situation is driving at dark (there are no road lights and more people are drunk. I've also seen some vehicles without any back lights!
Police emergency call is 191
There's not much more danger by consuming food and beverages than in the industrial countries. The hygienic conditions are a lot lower though.
I stayed several weeks there and drank tap water as well as ice cubes (well, melted ones). Also I have aten a lot off the markets and street restaurants (if you want to call them that). There was never any problem.
>>> VIRUSES AND BACTERIA
Bird flu is not common in the vicinity. There is no malaria and rarely hepatitis.
>>> MEDICAL CARE
The standard ist very low. I've seen a rural hospital with a dormitory with 12 beds, just fans and insects all over the place. MDs not attached to hospitals are very rare around here. If you get ill you want to go the really big cities like Khon Kaen, Udon Thani or even Ciang Mai. The best hospitals are of cours located in BKK.