Often dubbed as the northern Thai version of the popular tom yum, this spicy and sour soup consist of a flavorful broth that is usually infused with kaffir lime leaves, Thai basil, lemongrass, and galangal. Although it is traditionally prepared with beef and beef offal, some variations may include pork or water buffalo.

The soup is often additionally enriched with fish sauce, lime juice, or tamarind. It is usually served garnished with chili flakes or fresh chili peppers.