A teenage waitress overdosed on caffeine after drinking 14 shots of espresso.
Jasmine Willis, 17, could hardly breathe and was taken to hospital with a high temperature and heart palpitations.
She had drunk almost three times the recommended daily amount of caffeine in just four hours.
Miss Willis, a student, was working part-time out in her father Gary's recently-opened sandwich bar after sitting her GCSEs.
She began her coffee binge last Wednesday after getting only five hours' sleep the previous night.
"I decided to have a double espresso to perk me up," she said. "It did the trick so I had one after another and they seemed to be working. I felt great - as if I could take on the world."
By noon she was feeling unwell and crying and laughing uncontrollably in front of bewildered customers.
Miss Willis said: "My nerves were jangling. Tears were streaming down my face. People kept asking me if I was all right."
Her father sent her home but by the following morning she could not feel her lips and was struggling to breathe.
Miss Willis, from Stanley, County Durham, spent several hours under observation at the University Hospital of North Durham, where the caffeine overdose was diagnosed.
She said: "I was drenched and burning up and hyperventilating.
"I was having palpitations, my heart was beating so fast. I think I was going into shock".
Miss Willis is due to start her Alevels at college next month, studying law, psychology, sociology and accountancy.
She said last night: "Coffee is fine in moderation and really does pick you up, but I just overdid it. I didn't realise what could happen, so I hope other people learn from my mistake."
"I felt exhausted for days afterwards and I can't even bear the sight of coffee now".
Her father said: "Jasmine was just helping out in her holidays and had started on the 8am shift.
"She doesn't usually drink coffee at all, not even instant. But I've just had a beautiful new coffee machine installed so she thought she'd try an espresso."
The Department of Health advises people not to drink more than five single espressos or four cups of instant coffee a day.
The Bristol University team found that the levels of alertness among those who drank coffee were almost the same as those who had drunk none.
Coffee has been found to have some health benefits, however, Studies have suggested it can protect against the onset of Parkinson's disease and keep the mind sharp into old age.
A spokesman for the British Coffee Association said: "There are thousands of published studies which demonstrate clearly that moderate coffee drinking - four to five cups a day - is perfectly safe.
"Increasingly, there is evidence to suggest that there are health benefits from it. The key to any healthy, balanced diet is moderation in all things and this applies to coffee."
Source: DailyMail.co.uk