|Alternative names||Chicken coconut soup, galangal soup|
|Place of origin||Thailand and Laos|
|Main ingredients||Coconut milk, galangal, lemon grass, kaffir lime leaves, mushrooms and chicken|
Tom kha kai, tom kha gai, or Thai coconut soup (Thai: ต้มข่าไก่, pronounced [tôm kʰàː kàj]; Lao: ຕົ້ມຂ່າໄກ່, pronounced [tôm kʰāː kāj]; literally "chicken galangal soup") is a spicy and sour hot soup with coconut milk in Thai.
In Thailand, most tom kha kai recipes typically include coconut milk, galangal, kaffir lime leaves, lemongrass, Thai chili , coriander (or dill weed), straw mushrooms (or shiitake or other mushrooms), chicken, fish sauce, and lime juice. Fried chilies are sometimes added.
In a Thai-style tom kha kai, dill weed is not used, whereas in a Lao-style tom kha kai, dill weed (phak si, Lao: ຜັກຊີ) is used. Dill weed is a common herb which is used in Lao cuisine. The Thais' answer to dill weed (known in Thailand as phak chi Lao (Thai: ผักชีลาว), since it is known locally as a Lao herb) in Thai tom kha is coriander or cilantro (phak chi, Thai: ผักชี).
There are other versions of tom kha kai made with seafood (tom kha thale, Thai: ต้มข่าทะเล), mushrooms (tom kha het, Thai: ต้มข่าเห็ด), pork (tom kha mu, Thai: ต้มข่าหมู) and tofu (tom kha taohu, Thai: ต้มข่าเต้าหู้).
In the late 19th century, tom kha was not a soup. It was a dish of chicken or duck simmered in a light coconut broth with a generous amount of galangal. It was then served with a basic roasted chili jam as a dipping relish.