Leftover medicine from before the apocalypse is still lying around everywhere. You can find it in piles of scraps and at some map locations. You can even try to replicate the lost arts and attempt to make them yourself.
- Medicine can be used in the infirmary to quickly heal Lasting Damage your survivors incurred. It is by far the fastest way to heal your people.
- You can also use medicine to craft first aid kits. Those can only heal temporary damage.