carmendrahl writes "Emergency-room visits linked to caffeine-laden energy drinks are on the rise. This gives scientists who'd like to see caffeine regulated the jitters. But the U.S. Food and Drug Administration seems to be dragging its feet on regulating caffeine content in food and drink, because people have different sensitivities to it (abstract). Currently, caffeine-rich products like Monster Energy get around the rules because they're marketed as dietary supplements. 'Caffeine gets cleared from the body at different rates because of genetic variations, gender, and even whether a person is a smoker. For this reason, it’s difficult to set a safe limit of daily consumption on the compound. Physiological differences, as well as differences in the way people consume caffeine, have tied FDA in knots as it has debated how to regulate the substance. ... The toxic level in humans, about 10 g, is roughly the equivalent of imbibing 75 cups of brewed coffee (in 8-oz mugs) or 120 cans of Red Bull over a few hours. But that lethal limit can vary widely from person to person, experts say."