Coca-Cola and PepsiCo sell energy drinks, such as Monster and Red Bull. Other brands are 5-Hour Energy and Rockstar.
All energy drinks contain large amounts of caffeine and often sugar. They are sold as a way to boost performance, focus or overall health.
Since 2009, five deaths have been linked to energy drinks. Emergency room visits related to the drinks went from 1,128 in 2005 to 13,114 in 2009.
Senator Richard Durbin of Illinois want the safety of the drinks reviewed. One 16-ounce can of Monster has 160 milligrams of caffeine. This equals almost five cans of soda. Experts say young people should not have more than 100 milligrams of caffeine a day.
The FDA limits caffeine to 71 milligrams in 12-ounce soft drinks. To get around this rule energy drinks call themselves dietary supplements.
Recently, a couple said their daughter went into cardiac arrest and died after drinking two 24-ounce Monster energy drinks in 24 hours. They filed a lawsuit blaming the company.
As of now, there is no evidence linking energy drinks to heart problems. The company says it has followed all laws on labeling drinks.
Energy drink sales went up by 17 percent last year.