This is a tangent, but snake oil was medicinally effective.
The colloquialism "snake oil salesman" comes from the old scam of confidence men selling a cheap, adulterated (and sometimes drugged) mineral oil as snake oil (based on the Chinese water snake from Chinese traditional medicine). People would pay a premium for what they thought was medicine, only to find out later that the confidence men bamboozled them and skipped town with their money.
The colloquialism "snake oil salesman" comes from the old scam of confidence men selling a cheap, adulterated (and sometimes drugged) mineral oil as snake oil (based on the Chinese water snake from Chinese traditional medicine). People would pay a premium for what they thought was medicine, only to find out later that the confidence men bamboozled them and skipped town with their money.
https://en.wikipedia.org/wiki/Snake_oil