A patent medicine, also known as a nostrum (from the Latin nostrum remedium, or "our remedy") is a commercial product advertised (usually heavily) as a purported over-the-counter medicine, without regard to its effectiveness.
Patent medicines were one of the first major product categories that the advertising industry promoted; patent medicine promoters pioneered many advertising and sales techniques that were later used for other products.Patent medicine advertising often marketed products as being medical panaceas (or at least a treatment for a large number of diseases) and emphasized exotic ingredients and endorsements from purported experts or celebrities, which may or may have not been true. Patent medicines were increasingly constricted in the United States in the early 20th century as the Food and Drug Administration and Federal Trade Commission added ever-increasing regulations to prevent fraud, unintentional poisoning and deceptive advertising. Sellers of liniments, claimed to contain snake oil and falsely promoted as a cure-all, made the snake oil salesman a lasting symbol for a charlatan.
The phrase "patent medicine" comes from the late 17th century marketing of medical elixirs, when those who found favour with royalty were issued letters patent authorising the use of the royal endorsement in advertising. Few if any of the nostrums were actually patented; chemical patents did not come into use in the United States until 1925. Furthermore, patenting one of these remedies would have meant publicly disclosing its ingredients, which most promoters sought to avoid.
Advertisement kept these patent medications in the public eye and gave the belief that no disease was beyond the cure of patent medication. “The medicine man’s key task quickly became not production but sales, the job of persuading ailing citizens to buy his particular brand from among the hundreds offered. Whether unscrupulous or self-deluded, nostrum makers set about this task with cleverness and zeal.”