I'm trying to remember the title of a historical fantasy novel that I read many years ago (say, 2002) and it was pretty old back then. The story is set in China and involves the adventures of a disciple and his master (possibly a magician or a sage or something like that). One of their tasks was to hunt for the rare ginseng herb possibly in order to create an antidote. I guess that this is a pretty obscure description. The stories might have revolved around ancient Chinese fables.
While this may also be inexact, I recall that the author might have been famous or at least well-respected in the genre. The names of the two characters might have rhymed. I can also picture a large lake full of lanterns in the midst of which sits a royal personage. There might have been a tiger or a character named so.