From a review...

...in the Times of a new book, Caffeinated: How Our Daily Habit Helps, Hurts and Hooks Us (my emphasis):

From its beginnings in the late 19th century, Coca-Cola was advertised as a stimulant. In 1909 the federal government seized an interstate shipment of syrup, charging that the beverage’s caffeine content violated the Pure Food and Drug Act. It took five years for the Coca-Cola Company to win that case, whereupon it promptly reduced the amount of caffeine in the proprietary formula.