Not to be confused with allopathy, although since both are responsible for "killing", they may be related in ways we do not know!  After all, a lot of drugs come from plants, right? 

https://www.gardeningknowhow.com/garden-how-to/info/allelopathic-plants.htm

In the link below (describing allopathic medicine origins) there is an interesting section as you scroll down, concerning Dr. Benjamin Rush.  He was dangerous, in my opinion, and probably caused more deaths than anything.  He was also the father of  "psychiatry" which makes him a quack, as far as I'm concerned.

http://naturalhealthperspective.com/tutorials/allopathy.html