t 11,000 feet above sea level, the Cusco airport offers arriving passengers dry coca leaves for chewing—a millennia-old practice locals keep alive today. Coca leaves are ubiquitous in the historical capital of the Inca Empire in the Peruvian Andes. Throughout the surrounding Sacred Valley, hotels welcome tourists with bitter, earthy, and herbaceous coca tea to combat soroche (altitude sickness), bars serve coca-infused pisco cocktails, and bakers grind the leaves to make bread. The leaves are part of the cultural, culinary, and ecological fabric of the region.

Meanwhile, in the United States, coca leaves have two primary associations, neither of which is quite so wholesome: cocaine and Coca-Cola. In 1961, the United Nations declared coca leaves an illegal narcotic, and, outside of countries like Peru and Bolivia, it’s illegal to use the plant. But one US company was given a pass.

Coca leaves and kola nuts gave Coca-Cola its name and its distinct flavor, and cocaine—an isolated alkaloid from coca leaves that, in ultra-concentrated form, becomes the addictive narcotic—was once an ingredient in the drink. An advertisement from the late 19th century, when cocaine was legal in the United States, promoted Coca-Cola as a promising brain tonic that relieved headaches and mental or physical exhaustion. Another swore that Coca-Cola syrup cured nervous afflictions, with drugstore soda fountains soon becoming a vehicle to dispense over-the-counter doses to customers.