Black laborers in the New Orleans area began using cocaine to help them get through long, hard days of physical work.
But, Cohen writes, within just a decade, public attitudes regarding cocaine changed dramatically. This had everything to do with the drug’s adoption by the southern Black working class. Around the time Candler assumed control of Coca-Cola, Black laborers in the New Orleans area began using cocaine to help them get through long, hard days of physical work. Cocaine use spread to workers at plantations and in urban areas around the South. It also became a popular recreational drug in Black and mixed-race neighborhoods.
While the medical profession had seen nothing wrong with tonics such as Coca-Cola advertising themselves to white, middle-class consumers for their aphrodisiac qualities, it became an entirely different matter when Black people used cocaine. Medical journals warned of the “Negro cocaine menace.” Newspapers claimed that the drug caused Black men to commit crimes—most notably, raping white women.
https://daily.jstor.org/who-took-the-cocaine-out-of-coca-cola/