Two young men who are believed to have been served with two shots of anti-freeze at a London pub are taking legal advice.
The two friends thought they were drinking aftershock
Ian Harber and Jamie Anderson were on a night out when they ordered two shots of Aftershock, a blue liqueur, at the Bear and Ragged Staff in Crayford, Greater London.
But within seconds of swallowing the drinks they were violently sick, as were two bar staff who tested the drink themselves. All four were rushed to hospital.
One theory being investigated is the contents of a display bottle in the back bar may have been served up by mistake.
Mr Harber, 22, from Dartford, Kent, said: "There was a burning sensation all down the throat into the stomach which then caused immediate pain and vomiting.
"I was informed by a doctor that anti-freeze is worse than drinking bleach and apparently it can strip paint from a car."
Doctors were convinced they had drunk anti-freeze which, without treatment, could have caused kidney damage and blindness.
Ian Harber is considering legal action
As the antidote is strong alcohol, the patients were made to drink seven glasses of whisky in half an hour.
Environmental health officers and trading standards have begun an investigation following the incident on 26 July.
They are looking at whether a display bottle on the back bar had been filled with anti-freeze and served by mistake.
The Greene King Pub Company, which runs the Bear and Ragged Staff, has also begun an investigation.
A spokesman said: "Greene King does not store anti-freeze in any of its pubs nor use it in its business.
"The company is not ruling out malicious sabotage.
"The house managers responsible for the back bar display have been suspended."