The herbalist was an old woman who resided in the ruins of Taku. Aang sought her help when his friends became ill.
This octogenarian devoted forty years of her life to making herbal medicines for wounded Earth Kingdomtroops at an abandoned medical institution. For a time, she was the only person living in and taking care of the institute, as all her students left the area to support the war effort. Her only companion was Miyuki, her beloved cat.
Aang learned that the herbalist lived at the top of a nearby mountain, and traveled there to find a cure for Sokka and Katara after they fell ill. After a brief yet frustrating meeting with him, the old woman told Aang that his friends must suck on the frozen bodies of hibernating frogs to be cured, which could be found in many of the region's riverbeds.