Yes, a snake oil salesman sells a product that promises the earth but doesn't (of course) deliver.
"Snake oil" is therefore a generic term for something that's too good to be true.
I actually saw a snake oil salesman in action in Bolivia, and very good he was, persuading very poor farm workers to cough up large (to them) sums of money for snake oils and creams which would cure every conceivable illness, increase a man's potency, increase a woman's fertility etc. Very sad to see, but for desperate people it was the only hope of medical care they could afford.
Duncan
