Tobacco can be used as an insecticide, and also for deworming livestock. At one time it was even prescribed to people for getting rid of intestinal parasites.
Hmm, I’d read somewhere that the Feds could get you for that, when I’d considered growing my own. Guess they must have been talking about commercial operations.
I did know about the other uses though. The Army survival manual still advices eating a cigarette or two to get rid of intestinal parasites if you are out in the wild and can’t get proper medical attention. Of course, that will make you sick too, but as long as you only eat a small amount, it won’t kill you.