Monster Beverage is famous for its caffine and sugar-filled energy drinks, but it may soon find itself having to defend its beverages in court.

In a complaint filed in a California Superior Court, Monster Beverage is being sued over the death of a 14-year-old girl named Anais Fournier. The girl’s family, from Hagerstown, Maryland, alleges that the girl died after drinking two 24-ounce cans of Monster Energy drinks within 24 hours.

According to an AP report, an autopsy performed Fournier’s death found that she had died of cardiac arrhythmia due to caffeine toxicity. The caffeine had made the girl’s heart pump irregularly, preventing it from pumping blood properly. In addition to the caffeine, the AP reports that the girl had inherited a disorder that “can weaken blood vessels.”

Obviously, Monster doesn’t believe its drinks caused the girl to die, and has vowed to “vigorously” fight the lawsuit. The company stated that it does not know of any deaths caused by its drinks.

A Bloomberg report, however, shows that Monster Energy drinks have been linked to the deaths of five people in the past year. Five different reports received by the U.S. Food and Drug Administration (FDA) show that Monster drinks were consumed prior to patient deaths.

Monster Beverage stock is down today following the news. The price dipped as low as 43.60, an almost 19% drop from the day’s high. Monster Beverage opened today’s trading at 53.32.