Medical knowledge and medical materials are at an impasse. We know far more than we can utilize with the materials in Mercy, but ingenuity goes a long way.
Materials and procedures able to be performed are from the early 20th century time period. Though our knowledge of medicine FAR exceeds those procedures, we are beholden to what we have available. Surgery exists, but not modern science surgery on more critical procedures. Through roleplay and discovery, medicine can advance and the free society of Mercy might influence those from the towers to do so. Healers and doctors do exist in Mercy, but at greatly reduced abilities to those from the Towers that specialized in such. Those in Mercy could have a lot to learn if those from the Towers wish to share with them, and those from the Towers will need materials and items if those in Mercy wish to share.
Drugs Available:
All natural herbal remedies should be easy to find by anyone
Cannabis is widely available, but the best stuff is at the bordello
Aspirin and basic pain relief/fever reducers are easily traded for
Only by those in the Medical/Tech Co-Op:
Ether (Sulfuric acid can be obtained from onions and some minerals, alcohol from the Brewmaster and a chemistry lesson later, you have Ether)
Opium/Morphine/Laudanum (traded to the bordello and available there for recreation)
Epinephrine
Penicillin
Most drugs available pre-1930 or able to be produced with available technology can be used. A mix of old-world medicine, modern knowledge and ingenuity are in order!