The golden rule is: If you cannot peel it, boil it or cook it -- do not eat it. Generally, try to avoid fresh salads or raw vegetables as they may be washed with contaminated water and avoid eating raw shellfish, raw crab and cold cooked meats.
In large cities, the tap water in hotels and restaurants is fine but otherwise you are best to stick to bottled water, even for brushing your teeth. Purify all water by boiling for ten minutes (or just buy bottled water).
Purifying tablets are not as effective as boiling, but some protection is provided by adding iodine or Puratabs. Use four drops of iodine to one litre of water and let it stand for forty minutes. Do not use iodine for extended periods or if you have thyroid problems. Otherwise drink bottled water, which is much more affordable than in the west, and make sure the seal is not broken.
You may come across crushed ice in your drink and live to tell the tale, but be aware that ground up ice, although manufactured with clean water, is open to contamination when it is transported as the large blocks come into contact with the ground. Ice cubes with holes through the middle should be safe.
Please find below some of the more frequently asked questions (FAQ) people have about travelling to Thailand. We've tried to answer all the most frequently asked questions, but if you have another query about Thailand, please try our Travelfish messageboard.
Is it possible to rent rooms or dormitories for long periods of time?
Rooms: is a fan room ok, or should I budget for air-con?
Should I take my own padlock for the door of my room while travelling in Thailand?
What should I do if a bag is stolen from my room or dormitory while travelling in Thailand?
What standard of acommodation can I expect for US$5?
Why are there so few dormitories in Thailand?
Can I drink the tap water in Thailand?
How can I avoid MSG in Thailand?
How do I avoid peanuts in Thailand?
I have a food allergy - will I cope?
Is there good vegetarian food in Thailand?
Is western food available in Thailand?
Are the ferries in Thailand safe?
Are the trains in Thailand safe?
Do they trains run on time?
Is it easy to hitch-hike in Thailand?
Is it easy to rent a car or motorcycle in Thailand?
Should I get a tourist minibus in Thailand?
What is Bangkok's bus system like?
Which is the better way to travel around Thailand - train or bus?
Are credit cards accepted in Thailand?
Are there ATMs in Thailand?
How can I have money sent to me in Thailand?
How can I send money out of Thailand?
Should I bring travellers cheques, credit/debit cards or cash to Thailand?
Should I tip in Thailand?
Are leeches a problem in Thailand?
Are legal drugs cheap in Thailand?
Do I need a prescription in Thailand?
Do I need malarial medication in Thailand?
General health advice for Thailand
HIV/AIDS in Thailand
Is cholera a problem?
Is heatstroke a problem in Thailand?
Is medical care cheap in Thailand?
Is medical care in Thailand good?
Is rabies a problem in Thailand?
Schistosomiasis in Thailand?
Traveller's medical kit for travel in Thailand
What about dengue fever in Thailand?
Will I get diarrhoea in Thailand?
Are there many internet cafes in Thailand?
Can I travel with a laptop in Thailand?
Is there ADSL internet access in Thailand?
What is mobile phone coverage like in Thailand?
What is the voltage in Thailand?