There's a new warning about those popular energy drinks.
According to a study from the University of Michigan, those drinks can be dangerous when mixed with alcohol, used before exercise, or served to kids.
The drinks typically contain sugar, high amounts of caffeine, and taurine. Those ingredients can increase heart rate, put a strain on the body, and cause addiction.
However, doctors say the drinks are safe if used responsibly. That means not drinking two and three a day.