There’s an old joke in Kentucky about drinkers in the state during Prohibition—if you go on enough distillery tours, you’ll have eventually heard it so many times you can no longer even feign laughter. Drumroll, please, ’cause here it goes: Back during the so-called dry days, the only way you could legally get whiskey was by a doctor’s prescription. Suffice to say… there were a lot of sick people in Kentucky during those years.

Yes, as improbable as it sounds, the Volstead Act of 1919 didn’t completely shutter every distillery. Amazingly, six companies were granted the ability to sell what is now known as “medicinal” whiskey, all of it bottled-in-bond at 100 proof, government stamped, boxed up and with your prescription attached to the back. Sick (or, rather, “sick”) patients were allowed to purchase a pint from their pharmacy every 10 days, for about $3 apiece.

What qualified for a prescription? Any of a number of things: high blood pressure, pneumonia, digestive issues, tuberculosis. While referred to as medicinal whiskey, these were “bottled in bond” distillates no different than those sold before or after the era. The most significant changes were in the packaging. But they’ve still flown under the radar, and can be had for prices well below other whiskies bottled before and after Prohibition.

“These are not necessarily connoisseurs’ bourbons,” says Joshua Feldman, a whiskey historian who writes at the Coopered Tot, and has long collected examples from the era. “They’re historical more than anything.”

Unlike many whiskey collectors, Feldman is interested in learning what his acquisitions taste like, rather than simply sitting on a valuable, sealed bottle. “My thing is [writing] history with tasting notes, so I’m looking for tastes,” he explains. He’ll often write long posts about how a distillery’s general flavor profile has changed over the decades. And he’s constantly searching for off-the-radar estate sales where he might find forgotten bottles for a decent price. “My desire is to be storyteller and, in my fantasy, I crack and drink absolutely everything.”

Feldman explains that it’s hard for a collector like him to know how any of these bottles have been stored in the intervening 80-plus years since they were bottled. Perhaps they’ve been in a cool basement since the 18th Amendment was repealed, but more often, they’ve been stored in grandpa’s boiling-hot attic. “The thing about cracking Prohibition whiskey bottles is you never know what you’re gonna get,” adds Feldman. “Sometimes it’s great. Sometimes it’s quite bad.”

Below, a few notable bottles from Feldman’s collection of Prohibition-era medicinal whiskey.

Old Overholt Whiskey

When the Volstead Act passed, Old Overholt was owned by Andrew Mellon, then Secretary of the Treasury under President Warren G. Harding. Distilled in the fall of 1921 and bottled at the end of Prohibition, in 1933, this is not Old Overholt as we know it, claims Feldman. He should know: He once organized a full-century vertical—100 straight years—of bottles of the beloved rye. Instead, this comes from Large Distilling Co. (check the tax stamp) in the Monongahela district of Pennsylvania, and is distilled from red rye as opposed to Old Overholt’s lighter rye. Notice the dosage cup atop the cap, which is no different than you’d see on a bottle of Robitussin today.

Sam Thompson Pure Rye Whiskey

Distilled in 1916, this nine-year-old rye came out right in the midst of Prohibition, in 1926. This is yet another example of Monongahela rye from Brownsville, Pennsylvania, in the heart of the region. Released at a younger age than many Prohibition-era whiskeys, which are often over-oaked, Feldman calls it an “opportunity to taste a potentially exceptional example of a vanished style.”

Harry E. Wilken Special Old Reserve

This 15-year-old bourbon, distilled in 1917 and released in 1932, comes courtesy the ad hoc American Medicinal Spirits Company (AMS)—the biggest company during Prohibition. Though it says the Harry E. Wilken Distillery on the label, Feldman notes that it’s more commonly known as Deer Run Distillery, which would later become Old Grand-Dad Distillery. Notice the unique bottle design, with ribbed lines running the length of it; it was a design hallmark meant to make counterfeiting more difficult. It’s also one of the more commonly available, and sought-after, examples from the time (in 2016, a bottle sold at auction for £825 or around $1,100).

Old McBrayer Whiskey

Another release from AMS—again, notice the ornate bottle design, which plays off the medicinal theme—this whiskey was aged from 1915 to 1933. Though early-1800s bourbon pioneer Judge William Harrison McBrayer’s name is on the label, this actually comes from Aaron Bradley Co. “The funny thing about these labels is they create this confluence of stories,” Feldman explains. “The front of the label is about one 19th-century whiskey person, but the whiskey is actually produced at another distillery with a whole ’nother story.”

Waterfill and Frazier

This “pure whiskey for medicinal use” was distilled at Daviess County Distilling Co., which was owned by A. Ph. Stitzel Distillery when Mr. Pappy Van Winkle was at the helm. It was Pappy, in fact, who came up with the cleverly economical idea to print his company’s always-changing age statements on a smaller label, which could be then placed above the main label. As Feldman explains, “Whenever you see that red mezzaluna label, you immediately know that’s Pappy Van Winkle.” At this point, Pappy had yet to produce the wheated whiskey he would later become famous for under the aegis of Stitzel-Weller.