UK Police and road safety campaigners have reacted angrily after it emerged that the controversial product, already banned in the US, is being sold on-line.
The pill, called Alcopal costs 20 pounds for a pack of 20, is said to neutralise alcohol in breath samples, the 'Mirror' reported.
Supplier Arthur Kibble claims a motorist on the limit can reduce their booze reading to almost zero, the 'Mirror' reported.
If the claims are correct, it could mean a driver who had drunk five pints could still be found to be under the limit.
Kibble, who admitted he had been caught drink-driving in 2002, bragged on his website about Alcopal "making all the difference" if a motorist is breathalysed.
"The product is for blokes like me who do go down to the pub and have more than just one pint," Kibble said.
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"You could lose your license, your job and your home all for the sake of being 1 per cent over the limit.
"I am not advocating that motorists get blind drunk and then try to drive. And I must stress that these tablets do nothing to improve the performance of a driver who has been drinking," he added.
But Kevin Clinton, from the Royal Society for the Prevention of Accidents, said that, "it's dangerous and stupid and may encourage people to drink and drive in the belief they can get away with it."
Police have warned that drunk-drivers using the pills would not get away with it.
Alcopal, reportedly manufactured in India, is said to lower the absorption of alcohol into the blood, so less is expelled from the lungs and breath tests do not give a true reading.
The active ingredient simethicone is commonly used to treat digestive discomfort.
The pills have been withdrawn in the US but are legally on sale in Britain, where 280 people die on average each year as a result of drink-driving.