Medical experts say a new device which allows spirits to be inhaled could lead to brain damage.
Vodka and absinthe can be inhaled through the nose or mouth
Bristol bar, Il Bordello, is believed to be the first in the country to use the Alcohol Without Liquid vaporiser.
Professor Oliver James, from Newcastle University, said: "This will not only make you very drunk very quickly but is also likely to increase the risk of direct alcohol damage to the brain."
Inventor Dominic Simler said the device would reduce the effects of hangovers.
Professor James, who is head of clinical medical sciences at the university, said: "This could do irreversable damage to the nerves, lead to swelling and possibly lead to dementia in the long term."
He added that people may be able to use the device to inhale alcohol for 20 minutes and still be able to pass a police breathalyser test.
Mr Simlar, from London, said: "There is a built-in safety device as it takes about one hour to inhale one shot of alcohol.
"It is hardly something people are going to get very drunk on."
Mr Simlar says he has sold about 50 machines which cost £1,500 each.
Il Bordello's owner, Liz Lewitt, said the bar had been "overwhelmed" with people using the AWOL machine.
"It is a novelty. People enjoy passing it around in a group."