Background: Energy drinks are promoted as solutions to prevent tiredness, which has caused that their consumption increased progressively. Objective: To review the current state of knowledge regarding energy drinks and their components, particularly the beneficial and adverse effects. Materials and methods: A broad search was performed in Science Direct, SciELO, Medline and Pubmed databases, employing different combinations of the following descriptors: energy drinks, marketing, caffeine, taurine, glucose, guarana, xantine, vitamins, pharmacology, heart rate, cognition, natural product, decision-making. Results: Although the commercial energy drink components and their concentrations are not clearly determined, there is not enough evidence to support the adverse effects of some of their most common components as caffeine and taurine. Conclusion: There are no conclusive studies to support beneficial effects of energy drinks, but instead there is enough evidence about the adverse effects of some of the most common components of these beverages. Many more studies are needed to determine the safety of energy drinks, which have a considerable toxic potential not adequately informed to the consumer.