Medicine is an item used in doctoring.
Medicine can either be purchased from traders, looted from raiders, or crafted at a drug lab using 3 cloth , herbal medicine and neutroamine (skill requirement: medicine 6+ and crafting 3+, the pawn must also be capable of intellectual work).
Best used for treating diseases and infections; misused if for standard injuries (unless a colonist is bleeding out faster than the herbal medicine completes to patch the wound).
Good enough for surgical operations in many cases, with a low chance of failure. If the doctor is bionic-enhanced, trauma savant or drug-enhanced then you can guarantee 100% success rate for most surgeries.