They have been using snake venoms in drugs/vaccines for decades
The venom generally attacks one part of the system which, of you have a normal system and in the dose you get either shuts it down or revs it into high gear.
But if you give it in a tiny amount to someone it may either jump start a system that is not working or cool down one that is over producing.
I believe they have found one that stimulates the pancreas to an over production of insulin. Which puts you in a coma allowing it to eat you. But if you have diabetes and you are given a light dose it may help keep your pancreas running.
Dosis sola facit venenum (only the dose makes the poison)