Caffeinated 'Vomit Drink' Nauseated North America's First City

Cahokia existed near the confluence of the Missouri and Mississippi Rivers from about 1050 to 1350 in what is now in St. Louis, East St. Louis and the surrounding five counties, and inspired short-lived settlements as far away as Wisconsin. The core of this society, Greater Cahokia, had as many as 50,000 residents in its heyday living amidst earthen mounds, some more than 100 feet (30 meters) in height, making it the largest prehistoric North American settlement north of Mexico.

http://www.livescience.com/22136-caffeinated-black-drink-first-city.html

Caffeine-loaded black drinks apparently dominated the heartland of America earlier than once thought — a beverage neither coffee nor cola, but instead brewed from holly leaves, researchers say.

The ancient people may have downed the brew before ritual vomiting as part of purification ceremonies, the scientists added.