Drinkers may be putting themselves at risk by mixing alcohol with energy drinks, a new report has warned.
According to a new study, caffeine in energy drinks can mask the effects of alcohol and make drinkers less aware of how drunk they are.
"Both caffeine and alcohol are diuretics, they cause the body to pass water, so mixing energy drinks with alcohol can leave drinkers badly dehydrated, possibly leading to vomiting, nausea, and other health problems in the long term," said Andrew Misell of the UK charity Alcohol Concern.
"What's more dangerous, perhaps, is that the stimulant effect of so much caffeine can mask the depressant effect of the alcohol.
"People drinking energy drinks with alcohol may feel very alert and not realise how drunk they are. One possible result of this is that drinkers will take more risks."
According to the charity, a study in the US found that students drinking alcohol mixed with energy drinks were four times more likely to intend to drive compared with drinkers who had consumed alcohol without energy drinks.
Favourite mixes of alcohol and energy drinks include the Jagerbomb (a shot of the 70pc-proof German digestif Jagermeister with caffeinated drink Red Bull) and the double vodka and Red Bull cocktail.
Alcohol Concern has urged energy-drink producers to warn consumers of the possible dangers of mixing their products with alcohol. It also wants bars and clubs to stop promoting energy drinks as mixers.