From Patent Medicine to Cocktail Ingredient
Many historic patent medicines contained large quantities of high-proof alcohol, if they weren't made up of alcohol entirely. The histories of patent medicines and cocktails have a good deal of overlap, as bitters and drinks like juleps have medicinal origins.
Bitters
Bitters consist of large quantities of high-proof alcohol infused with botanicals, from commonplace kitchen botanicals such as fruit peels and herbs to roots, barks, and flowers. They are now used as flavoring agents in a large variety of cocktails, but originally were advertised as all-powerful cures for a variety of ailments, often ailments of the stomach, or for the purification of the blood, which was commonly believed to be the source of many illnesses at the time.
Increasing alcohol taxes and the burgeoning of the temperance movement in the 19th century actually served to increase the popularity of bitters. Drinking was falling out of fashion in many circles but it was still commonly socially acceptable to take a daily "nip" of bitters for health purposes. Under tax classifications, alcohol-based bitters fell under the category of non-potable alcohol, and thus were exempted from newly-exorbitant taxes applied to the sale of spirits. These two factors resulted in a boom in the popularity of bitters and related patent medicines.
Bitters gradually fell out of common usage in America after the passage of the Pure Food and Drug Act, as the new restrictions on absurd advertising promises and the lowering of alcohol contents resulted in many imitation companies going out of business. However, some bitters had been adopted behind the bar for cocktail purposes, and you can still find some of these historic bitters brands on the shelves today, such as Angostura.
Fun fact: many bartenders swear that Angostura bitters are a perfect cure for the hiccups, a holdover from the days of bitters as restorative patent medicines.
Pabst Blue Ribbon
The overlap between alcohol production and patent medicines can be seen in these advertisements for the still existing Pabst Blue Ribbon company. In addition to the beers that the brand is contemporarily known for, these booklets advertise "The Best Tonic," a brewed beverage of malt and hops extract. The tonic promises to remedy dyspepsia, sleeplessness, sallow complexion, and lack of appetite, as well as to improve a shattered constitution, prevent declines in health, calm a distracted mind, brighten the eyes, rose the lips, and bring color to worn and pale cheeks.
Featured in the pamphlets are anecdotal stories, health advice, ailments that the product can cure, the farming process of the product, customer testimonials, a poem on don't's for baby raising, pages upon pages of jokes, and bountiful illustrations.
At the end of both booklets is a list of the products available from Pabst Blue Ribbon. The product list features five beers: select, bohemian, export, hofbraeu, and standard, as well as the way that they are packaged: bottle or keg, and The Best Tonic.
In the discussion of The Best Tonic there is no mention of any ingredients aside from malt and hops, but given the malt ingredient and the nature of Pabst's other products, as well as the claims to brighten the eyes and color the cheeks (both indications of an individual's high blood-alcohol content), it is likely that the tonic contained a fairly high alcohol content.