Medicine Is the Best Medicine
The quest is unlocked after completing The Great Plateau scenario.
"As the Calamity draws near, monsters are harming more people than ever. There's a shortage of helping hands, and not nearly enough medicine. Gather some materials with healing properties."
"The people of Hyrule were much more prepared for emergencies now that they had medical supplies. Plus, some of the residents of Castle Town offered to help administer treatments."