Peruna, "the most prominent proprietary nostrum in the country" in the early part of the 20th century, was much favored by bridge-playing old ladies and other discreet alcoholics, due to its high alcohol content.
Its astonishingly high alcohol content (28% in 1904), and its manufacturer's surprising candor about its lack of efficacy as a cure for "catarrh" (its supposed therapeutic target) in a conversation with investigative journalist Samuel Hopkins Adams led to a public backlash in 1905, upon publication of Adams's expose. This backlash, and the publication of Upton Sinclair's "The Jungle", were the impetus for the passing of the first Pure Food and Drug Act in 1906.
Peruna was reformulated to a lower alcohol content of 18% (the IRS had told the manufacturer to put some real medicine in the product or to "open a bar"), but it never regained its former popularity. Prohibition did help to boost its sales again, however.