Myanmar does not require any mandatory vaccinations, except yellow fever, if you’re coming from an affected zone. However, Myanmar is host to a whole lot of pretty deadly diseases, so it’s recommended that you get a few vaccinations done beforehand, especially if you’re planning to travel quite a bit through the country or will be staying in rural areas. Among the more common maladies are rabies, cholera, typhoid, dysentery, malaria and hepatitis- all typically tropical diseases. It’s best to carry along some reliable medication (just in case), such as malaria pills. Also keep yourself well protected from the mosquitoes with insect repellent, and take care of what you eat and drink. Consume only boiled or bottled water, and don’t eat food which you might have cause to think isn’t fresh or hasn’t been handled hygienically.
Larger cities like Yangon and Mandalay have a fairly reliable medical system, but you’re unlikely to find any doctors or hospitals in rural areas- and Western medicines are almost totally unknown outside urban areas, so go prepared.
If you’re travelling to Myanmar, you should keep in mind the fact that clashes between pro-democracy forces and the military-controlled government can erupt at any time, and foreigners, especially Westerners, can come under scrutiny, or can be detained and even arrested at such times. It’s best to steer clear and not get involved in anything against the government, no matter how noble your intentions.
Also remember that some parts of the country-particularly northern areas that fall within the so-called `Golden Triangle’- are overrun by drug-runners and are unsafe. If you’re planning to travel north, check with your embassy in Yangon if it’s safe to do so. Even otherwise, if you’re keen on going anywhere off the beaten path, it’s wisest to check.
Violent crime is fortunately fairly low in Myanmar, although petty thefts occur. Take precautions when moving around, and beware of pickpockets.