In modern figurative use, snake oil refers to a fraudulent remedy, especially one promoted and sold by a quack. The quacks who push such products are snake-oil salesmen.
Origins and history
Around the late 19th century, the American cultural imagination created the figure of the traveling salesman who went about small towns and rural areas using charm and showmanship to sell supposedly miraculous elixirs and powders in public places. These cure-alls were usually fraudulent, but the salesman could get away with selling them because he would clear out immediately after doing business. Such salesman of course did exist, but by the 20th century they were mainly a folklorish figure, parodied by actors in stage shows and carnivals and often referred to for rhetorical purposes in writing on unrelated subjects.
Among the fraudulent products associated with these salesmen was snake oil, which was once a real thing. From what we can glean from early use of the phrase, it seems that the original oil was derived not from snakes but rather from the rattlesnake root, also known as the seneca snakeroot, so named because it resembles a snake’s rattle and also because it was believed to both repel rattlesnakes and cure their venom—folk wisdom apparently received from the Native Americans. In early use, the phrase was usually “rattle-snake’s oil,” and this was shortened to “snake oil” by the second half of the 19th century.
This passage, written circa 1730 by William Byrd, a Virginian, perhaps sheds light on the origin of the phrase:
I found near our camp some plants of that kind of rattle-snake root, called star-grass. … The root is in shape not unlike the rattle of that serpent, and is a strong antidote against the bite of it. It is very bitter, and where it meets with any poison, works by violent sweats, but where it meets with none, has no sensible operation but that of putting the spirits into a great hurry, and so of promoting perspiration. The rattle-snake has an utter antipathy to this plant, insomuch that if you smear your hands with the juice of it, you may handle the viper safely. [full text of The Westover Manuscripts]
That the later snake oil developed from rattle snake’s oil seems likely when we look at instances such as these, which are from the early 19th century:
A youth, affected with this disease, was relieved by taking an ounce of rattle-snake’s oil. ["Bilious Colics in Cumberland County, Maine," Dr. Jeremiah Barker (1801)]
They may be cured by soaking the foot in warm water till the corn is soft; … then supple it well in rattle-snake’s oil, or the nerve ointment. [New Guide to Health, Samuel Thomson (Boston, 1835)]
For hoarseness.—Take three drops of black snake’s oil, or of rattlesnakes’ oil, at bed time. [The vegetable materia medica and practice of medicine, Abel Tennant (Batavia, NY, 1837)]
The oil must not have worked as well as was claimed, because later that century we begin to see instances such as these, which, in our opinion, show the beginning of the phrase’s transition from its older use to the newer one:
With regard to dog fat, snake oil, ox-blood, and other disgusting specifics of that sort so highly vaunted by the laity, I have only to tell you that it is all nonsense to sanction their use. [The Medical Age (Detroit, 1885)]
The belief in “snake-oil” as a remedy is probably only one phase of the feeling which so often and among such different races has given rise to serpent-worship. [The Popular Science Monthly (New York, 1888)]
And all this in the face of legitimate pharmacy, while those pests and vampires reap dollars from the sale of snake oil, made of rot-gut whisky, a little ammonia and tincture of iron [Western Druggist (Chicago, 1895)]
That last example also contains an early reference to the figure of the snake-oil salesman.
Early-20th-century references to snake oil tend to be positive—and there were in fact well-known snake-oil salesmen active during this time, some claiming their elixirs contained oil actually extracted from snakes—though there are inklings in some scholarly sources that learned people regarded the popular belief in snake oil with amusement. The turning point comes around the second world war, after which snake-oil and snake-oil salesman almost invariably bear their modern senses and also begin to gain broader, figurative use—for example:
I should have had some snake oil along to sell to the suckers. [Billboard (1950)]
Professional workers tend to regard advertising as a technique to be employed only by quacks and frauds who peddle “snake oil” as a cure for all illnesses. [The American Secondary School, Leslie Owen Taylor (1960)]
Meanwhile, he develops a snake-oil salesman’s capacity to talk people into going out and skiing for him. [Skiing (1974)]
Finally, for good measure, here are a few recent examples showing how broadly the terms are now applied:
Olen is taking on the sellers of a particularly insidious form of snake oil, the idea that if you try really hard — and maybe pay $29.95 for a book … — you, too, can achieve financial success. [AP Big Story blog]
There are snake oil salesmen, who have no professional research, professional training or professional publications in the field of nutrition, and there are scientists, who have formal training, have conducted research and have reported on their findings in professional forums. [The China Study, T. Colin Campbell and Thomas M. Campbell]
Like Monster Cable and that $500 Denon Ethernet cable, there’s more snake oil flowing through this “premium” socket than anything else. [Gizmodo]
It might be the risk of meeting a snake oil salesman who convinces an investor to stake his or her entire savings on one dud investment. [New Zealand Herald]