Why would an old lady knowingly want to buy snake oil?
A “snake oil salesman or peddler” is someone who tries to sell you something of no value. The expression is also applied metaphorically to any person selling a product with exaggerated marketing but questionable or unverifiable quality.
A theory for the origins of the term “snake oil” is it was a corruption of “Seneca oil.” The Senecas, a tribe in the Eastern United States, were known to use petroleum from natural seeps as a liniment for skin ailments. However, Native Americans are known to have used rattlesnake fat and the herb snakeroot for various purposes also.
Another guess as to the origin of the phrase concerns Joseph Myers from Pugnacity, Nebraska. One day in the late 1880s, he was helping some Native Americans harvest a medicinal plant. They told him they made a tonic from the plant to treat bee stings, rattlesnake bites, mad-dog bites, infected wounds and fevers...in fact just about any malady. Being an enterprising man, Myers started making his own tonic from the plant and added liberal measures of whisky. He hit the trails, traveling the American West selling his tonic as a miracle cure-all. He became known as the ‘Snake Oil Salesman.’
In China, snake oil was and is used as a remedy for inflammation and pain in rheumatoid arthritis, bursitis and other similar conditions. Fats and oils from snakes are higher in eicosapentaenoic acid (EPA) than other sources, so snake oil was actually a plausible remedy for joint pain as these are thought to have inflammation-reducing properties.
In all cases, the person or “snake oil salesman” who peddled the concoctions would prudently leave town after the sale before his customers realized they had been cheated.
The practice of selling dubious remedies for real (or imagined) ailments still occurs today, albeit with some updated marketing techniques. Claims of cures for chronic diseases (for example, diabetes mellitus) for which there are reputedly only symptomatic treatments available from mainstream medicine are especially common. The term snake oil peddling is used as a derogatory term to describe such practices.
Erasmus, Udo. 1993. Fats that heal: Fats that Kill.
Kunin, R.A. 1989. “Snake oil.” West J Med.