Vegetarian food
Vegetarians won't have too many problems surviving in Thailand, with one significant exception: fish sauce (น้ำปลา naam plaa) is to Thai cuisine what soy sauce is to Chinese food, and keeping it out of soups, curries and stir-fries will be a challenge.
That said, Thailand is a Buddhist country and vegetarianism is a fairly well-understood concept, especially among Chinese Thais (many of whom eat only vegetarian food during several festivals). Tofu is a traditional Thai ingredient and they aren't afraid to mix it up in some non traditional dishes such as omelettes (with or without eggs), submarine sandwiches, and burritos. Since Thai dishes are usually made to order, it's easy to ask for anything on the menu to be made without meat or fish. Bangkok features several fantastic veggie and vegan restaurants, but outside of big cities make sure to check that your idea of "veggie" matches the chef's.
Some key phrases for vegetarians:
- phom kin jeh (m) / di-chan kin jeh (f) ผม(ดิฉัน)กินเจ "I eat only vegetarian food"
- karunaa mai sai naam plaa กรุณาไม่ใส่น้ำปลา "Please don't use fish sauce"
source: wikipedia