The availability of caffeine-containing energy beverages, combined with aggressive marketing and “urban legend,” has promoted their widespread use, particularly among adolescents. The caffeine content of these products is presently unregulated. Rapid growth in the consumption of these supplements has resulted in increasing reports of caffeine poisoning. This article provides a review of caffeine's pharmacokinetics and describes the clinical manifestations and management of caffeine toxicity. Suggestions for future research are also offered.