A painter and decorator died from a huge caffeine overdose after eating mints bought from his local sweet shop, not knowing they were packed full of the stimulant.
John Jackson, 40, was found dead by relatives at his West Midlands flat after eating Hero Instant Energy Mints.
Just one of the sweets is said to contain more caffeine than a whole can of high-energy drink like Red Bull.
Coroner Robin Balmain told an inquest in Smethwick he would be writing to the Department of Health demanding answers over Mr Jackson's death.
He said: "This is a potentially very dangerous situation. The level of caffeine is enormous. I think it's as certain as it can be that Mr Jackson didn't know that he was going to expose himself to this sort of danger."
The mints are sold alongside other sweets, but makers Hero Energy Ltd, based in Birkenhead, stressed they had taken a series of measures to warn about the high caffeine content.
Mr Jackson was found dead by his estranged partner and stepdaughter at his flat in Darlaston on May 2.
A post-mortem examination showed he had 155mg of caffeine per litre of blood in his system, and just 10mg would have been considered an overdose, according to pathologist Dr Dragana Cvijan.
She told the inquest: "The most important compound found in the post-mortem was caffeine. I must say this is the first time in my experience that I've come across a caffeine overdose."
She gave the medical cause of death as caffeine toxicity, but said Mr Jackson, a heavy drinker, also had cirrhosis of the liver, leaving him unable to absorb the stimulant properly.
Stepdaughter Rebecca Court, 23, from Tipton, said Mr Jackson had bought the mints from a local shop.
"On the box they said one tablet equals one can of energy drinks. A kid could go in and buy them and the same thing could happen to him," she said.
Paul Hayes and Steve Hones, the directors of Hero Energy Ltd, issued a statement saying they were "shocked and deeply concerned" at Mr Jackson's death.
Warnings about the mints are clearly marked on packaging, websites, and shelf displays, including the advice not to consumer more than five in 24 hours, they stressed.
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