Drink lots of water. Never drink tap water purified, bottled water is available everywhere.
Use an insect repellent against mosquitoes. It is the only way to be sure of protection against mosquito borne diseases. Since this region generally has a hot and humid tropical climate, casual and light-weight clothing is best. Clothing made from natural fibers is the best option. A jacket might be needed on cool winter evenings or in hotels and restaurants using excessive air-conditioning. A hat and high-factor sun block is advisable as protection against the hot sun when sightseeing.
Although no vaccinations are officially required for this region, visitors are advised to check with their doctor or a travel immunization clinic regarding protection against malaria, typhoid, tetanus, hepatitis A and B
Pack medications in their original, clearly labelled, containers. A signed and dated letter from your physician describing your medical conditions and medications, including generic names, is also a good idea. If carrying syringes or needles, be sure to have a physician’s letter documenting their medical necessity. If you have a heart condition bring a copy of your ECG taken just prior to travelling.
If you happen to take any regular medication bring double your needs in case of loss or theft. In most Southeast Asian countries you can buy many medications over the counter without a doctor’s prescription, but it can be difficult to find some of the newer drugs, particularly the latest antidepressant drugs, blood pressure medications and contraceptive pills
Oh – and don’t forget… Drink lots of water!