Hopefully you will not need any! But, it is good to know that there are some excellent, English speaking doctors here. There is a brand new hospital here in Vallarta, San Javier and really is as nice or nicer than any I have seen in the US. Located across the street from the terminal marina.
Nearly every single hotel-accomodation has a purified water system. All ice and water in restaurants will be purified. Food also. Normally, what happens is that people arrive to PV, bake on the beach all day drinking beer after beer, hit the happy hours with snacks, eat new and heavy and spicey food, dance in the discos til the wee hours doing tequila shots, wake up in the morning sick and then blame the water! Their bodies are in shock! The sun and alcohol can be a lethal combination so take it easy, especially the first few days! If you feel more comfortable with bottled water brushing your teeth, etc then go for it. You will see nearly everyone walking around with bottled water and it is available everywhere. I would not recommend drinking water from the water fountains in the streets though. Otherwise, you should be fine.
Puerto Vallarta is basically a very, very safe place. You will see the tourist police in the downtown. These are the ones with white uniforms and safari hats. Most speak some English so do not hesitate to talk to them. I would suggest NOT walking on the beach at night alone, flashing large amounts of money and jewels. Be aware of what is going on around you and you will be fine. Becoming out of control in the bars-discos often leads to trouble so be careful!
While downtown (maybe it just happened to be while we were there, hmmmmm...) you'll see the 'PV Cops' driving around town. I don't know about anyone else,...but we decided to BEHAVE that night!!!:) YIKES is that an AK10?????
They had their flashing lights on constantly (as IF we didn't know they were there!!!)
We came to a final conclusion they're not as horrific as their appearance. We passed them in our little rented VW bug once, I was standing out the sunroof videotaping downtown life AND the cops as we passed them (semi expecting they'd pull us over yet taking the chance anyway), and they simply honked!! Now, was that a friendly honk or a warning honk???......