“The Cold Moons” is a 1987 novel by Aeron Clement about somewhat anthropomorphic badgers in the British wilderness. Its shown that badgers understand basic medicine. Tendril heals Bamber's torn and sore paws using a mixture of water, chewed grass, and chewed herbs. The badgers of the Cilgwyn forest have a badger specifically dubbed "the Healer" who helps heal sick badgers.
In the Terry Pratchett Discworld novel “A Hat Full of Sky” Tiffany learns the Doctrine of Signatures from Miss Level, based on a real-life medieval idea that God placed a "signature" on every plant that indicated its medical use, to those who could read it properly. This being Discworld, the signatures are literal, and with a special magnifying glass, you can read them on the stems. Sadly, plants are terrible spellers, but Miss Level has worked out a great many cures this way, such as goldenrod being good for jaundice, which turns skin yellow.
Its established in several of Terry Pratchett’s Discworld novels that most of Granny Weatherwax's potions work on the placebo effect (she tells one patient that it contains rare herbs like "sukra and akwa"😉, she does have a herb garden full of unusual plants for when that isn't enough. "The Sea and Little Fishes" says that medicinal plants are sometimes called simples, but Granny's herbs are complicateds.