Normally, you would use herbalism for that, but check with your DM
The Medicine skill is described on page 178, PH. It says
Medicine.A Wisdom (Medicine) check lets you try to stabilize a dying companion or diagnose an illness.
You are not alone in trying to find some use for this: Is there a real use for the medicine skill?
As written, medicine does let you diagnose sea sickness, but does not explicitly allow you to prepare a curative herbal brew. That would normally fall under proficiency with the Herbalism Kit:
Herbalism Kit. […] Proficiency with this kit lets you add your proficiency bonus to any ability checks you make to identify or apply herbs.
That said, the things listed under the skills are examples (p. 171 PH)
The skills related to each ability score are shown in the following list. […] See an ability’s description in the later sections of this chapter for examples of how to use a skill associated with an ability.
So check with your DM. Even though there is an explicit kit proficiency for what you aim to do, Medicine is not one if the most useful skills the way it is written (especially since with a simple 5 gp healer's kit, anyone can stabilize a creature without needing to make ana Wisdom (Medicine) check.) It may be that your DM also recognizes this and interprets what medicine can do more broadly. I would.