Fake bottles of vodka which could cause blindness or death to anyone who drinks the contents have been found on sale in five shops in Peterborough.
Genuine bottles have different markings from fakes
Trading standards officers said counterfeit 70cl bottles of Glen's Vodka had not been properly distilled.
Officials say the vodka contains high levels of methanol which could cause death or blindness in extreme cases.
The counterfeit batch is said to have a "strange" taste and the bottles are said to have non-standard markings.
Peterborough Trading Standards is investigating the case and said it was warning licensees and residents to only buy the product from reputable traders.
Genuine bottles should have a mark embossed on the glass bearing the name Allied Glass Containers and its AGC logo device and a code ending with the numbers 2173.
Counterfeit bottles are marked "Ayrshire" - and some bottles had the letter "i" missing from the word Ayrshire.
Donna Hall, a trading standards team leader, said: "I would urge traders to think twice before purchasing alcohol from unknown or disreputable sources.
"I would also remind food business operators of their legal responsibility to be able to identify their food suppliers."