The Medicine skill in 5e D&D doesn't really do much: "Medicine. A Wisdom (Medicine) check lets you try to stabilize a dying companion or diagnose an illness" (PHB 178). And that's it, rules as written.
The skill possesses an especially narrow utility since a healer's kit, which does not require proficiency for use, does the same thing without the need for a roll that could potentially fail: "As an action, you can expend one use of the kit to stabilize a creature that has 0 hit points, without needing to make a Wisdom (Medicine) check" (PHB 151).
If the user of a healer's kit has the Healer feat, the disparity is even greater because using a healer's kit now restores hit points and the Medicine skill as written never lets you restore hit points to a wounded creature.
Clearly, Medicine should have more going for it. Here are some (untested) suggestions:
- As an action, you can use the Medicine skill to allow a creature to spend a Hit Dice without taking a short rest by making a Wisdom (Medicine) check (DC 15) and expending one use of a healer's kit. A creature can't regain hit points from the Medicine skill again until they finish a short or long rest.
- As an action, you can use the Medicine skill to give a creature advantage on the next saving throw against a disease or poison they have already fallen victim to by making a Wisdom (Medicine) check (DC 15) and expending one use of a healer's kit.
- As an action during a short rest, you can use the Medicine skill to reduce a creature's level of exhaustion by one step by making a Wisdom (Medicine) check (DC 15) and expending one use of a healer's kit. A creature can't have their exhaustion reduced by this skill again until they finish a long rest.
I've made the above suggestions dependent on the healer's kit to curtail their overuse, but if they don't cause any unintended consequences in playtesting it would also be interesting to further test them uncoupled from healer's kit dependency.