The US Food and Drug Administration (FDA) Friday notified some 30 drinks manufacturers who combine alcohol and caffeine in their beverages that they must prove the products are safe.
"The increased popularity of consumption of caffeinated alcoholic beverages by college students and reports of potential health and safety issues necessitates that we look seriously at the scientific evidence as soon as possible," said Joshua Sharfstein, a deputy commissioner at the agency.
The FDA said it had received a letter from 19 prosecutors expressing "concern" about the products, saying it was not a safe mix.
Caffeinated alcoholic drinks have "been associated with dangerous behavior ... sexual assaults," said Mitchell Cheeseman, acting director of the office of food additive safety at the Center for Food Safety and Applied Nutrition.
The FDA "has not approved caffeine for use at any level in alcoholic beverages," the agency said.
For the first time the FDA has requested scientific evidence from the manufacturers that demonstrates the products are safe. The companies have 30 days to comply.
"We are asking their side of the story," said Sharfstein.
Already two major brewers, Anheuser-Busch and Miller, have agreed to discontinue their high-energy alcoholic beverages, sold as Tilt, Bud Extra, and Sparks.
If found to be deemed unsafe, the FDA will "take appropriate action to ensure that the products are removed from the marketplace," the agency said.