Talk to Tae Soo at Mu Lung: Peach Farm 1.
Collect 1 Peach Tree Herb Pouch from Mr. Do. The Peach Tree Herb Pouch is made from 20 Straw Doll, 20 Wooden Doll, and 20 Bellflower after obtaining the Book on Herbal Medicine by completing the quest Mr. Do's Book on Herbal Medicine.
Return and talk to Tae Soo.