> Strychnine, in small doses, was commonly used a stimulant at the time; today, the Centers for Disease Control and Prevention describes it as a “strong poison” that is “used primarily as a pesticide, particularly to kill rats.”

Trite as the saying is, the dose makes the poison.

Strychnine is similar to caffeine -- only orders of magnitude more potent, so that a couple of milligrams will stimulate your CNS, and a hundred milligrams will kill you. Caffeine, of course, will only stimulate you if you take more than about 100mg, and it'll only kill you if you take it by the teaspoon.

The strychnine derivative securinine (https://en.wikipedia.org/wiki/Securinine) was sold in Russia as a "safer" stimulant along the same lines as strychnine, until roughly the turn of the millennium. I enjoy experimenting with strange drugs -- and the Russian pharmacopoeia is as strange as it gets (the Italian one is also strange, with rubidium chloride as a stimulant!) -- so I've tracked down and tried securinine. Didn't notice much from it. Not much better than a strong cup of coffee. No discomfort, in any case.