摘要BACKGROUND: Caffeinated energy drinks are widely used worldwide. They are associated with a variety of adverse effects and are of concern to health authorities, yet there is still scarce information about their adverse effects and inadequate awareness among medical personnel. METHODS: Case description and discussion of a patient presenting to the emergency room after overdose of energy drinks in combination with 3,4-methylenedioxymethamphetamine (MDMA). RESULTS: Despite best medical efforts, the patient died of fatal cardiac arrhythmias. There is a paucity of information about adverse effects of energy drinks. CONCLUSION: Although energy drinks are widely used, there is a lack of awareness in the population and medical staff about their hazards.