Fun Down On the Farmpunk: Join in!

[Eldan]

Actually, I'd do it exactly the other way round.

Specific cures that help with one disease? Closer to the real world. Should belong in the city.

Magical cure-alls made from a handful of herbs? Folk magic.

My suggestion:

Patent Medicine: +6 against one disease or poison, works only in the city and the range.
Specific Medicines: +4 against one disease or poison, +1 against all. Work everywhere.
Cure-all: +3 against all diseases, work only in the wild or range.