Consumption of alcohol mixed with caffeinated energy drinks is becoming popular, and the number of pre-mixed caffeinated alcohol products on the worldwide market is increasing. There is public health concern and even occasional legal restriction relating to these drinks, due to associations with increased intoxication and harms. The precise nature and degree of the pharmacological relationship between caffeine and alcohol is not yet elucidated, but it is proposed that caffeine attenuates the sedative effects of alcohol intoxication while leaving motor and cognitive impairment unaffected. This creates a potentially precarious scenario for users who may underestimate their level of intoxication and impairment. While legislation in some countries has restricted production or marketing of pre-mixed products, many individuals mix their own energy drink-alcohol 'cocktails'. Wider dissemination of the risks might help balance marketing strategies that over-emphasize putative positive effects.