It’s said that during Prohibition, Islay scotches were the only ones legally allowed into the United States because its high iodine levels from the peat made it a medicinal spirit.

Whisky is made throughout Scotland but the most distinctive come from Islay (EYE-luh), an island off the west coast known as the Queen of the Hebrides. The island is rich in sea-soaked peat (the partly decomposed vegetable matter common to boggy, acidic ground) that is dug from the ground like turf, dried, and used as fuel for fires. Peat fires are used to dry the malted barley, imparting the smoky, briny medicinal flavors associated with the island’s distilleries like Ardbeg, Lagavulin, and Laphroig.

The Eighteenth Amendment to the U.S. Constitution banned the “manufacture, sale, or transportation of intoxicating liquors.” It took effect on January 16, 1920. Physicians could obtain a special permit from the Prohibition commissioner to prescribe alcohol, which the patient could then buy legally from the physician or pharmacist. They wrote prescriptions on a special pad issued by the U.S. Treasury.

Alcohol had been used for centuries for medicinal purposes. Part of its popularity was almost certainly due to its ubiquity and low cost. Doctors prescribed alcohol as a stimulant, preventative, tonic, and even a cure for some types of illness. Few depictions of the “Wild West” fail to include an injured or sick person swallowing whiskey or brandy. Patients of all ages – yes, even children – took alcohol as medicine.

Many physicians protested the imposition of Prohibition as an infringement on their right to treat patients with whatever necessary. They weren’t fighting Prohibition per se but the encroachment of government on the practice of medicine. While doctors could prescribe alcohol to patients, Prohibition did regulate the amount patients could receive.

Every ten days, patients could pay $3 for a prescription and another $3 or so to have it filled to receive a pint of booze. For many doctors and pharmacists, medicinal alcohol provided a means to make a few additional bucks.

Islay scotch may have found its way onto the prescription pads of American physicians because of its high iodine content. An essential trace element for life for its role in synthesizing thyroid hormones, iodine tends to concentrate in the water and soil of coastal areas like that of Islay. Iodine deficiency was endemic into the 1920s in the Great Lakes, Appalachians, and Northwest, a region known as the “goiter belt.” The introduction of iodized salt in 1924 significantly improved health across the nation. So, too, may have some Islay whisky.