Herbalist

History
This 80-year-old woman devotes her life to making herbal medicines for wounded Earth Kingdom troops. This old woman first came to the Herbalist Institute forty years before. She is the only person living in and taking care of the institute because her students all left long ago to help the Earth Kingdom armies. Her only companion is Miyuki, her beloved cat.(nick.com)

In the episode "The Blue Spirit", Sokka and Katara fall ill. Aang learns that the herbalist lives at the top of a nearby mountain, and makes plans to travel there to find a cure. Aang races through the mountainside, using his Airbending abilities to speed his pace. He soon arrives at the herbalist's home. After a frustrating meeting with the herbalist, Aang learns that his friends must suck on the frozen bodies of hibernating frogs, which can be found on the bottoms of riverbeds.