24 year old Cara Reynolds suffered a heart attack after taking Forza raspberry ketones, a popular herbal slimming pill, naturally occurring chemical compounds that give raspberries their scent, promoted as 'fat burners' .
Doctors who analysed the over-the-counter tablets said each contained as much caffeine as four cans of Red Bull.
Cara told her parents she planned to take them to help her lose weight while working out at the gym.
Her father said: 'She was 5'4" and a size 10. She wasn't overweight at all.
'But we wanted to be supportive of her. She told us the slimming pills were made from natural ingredients, so we didn't think they were anything to worry about.'
Her father Michael said many popular retailers should ban over-the-counter sales of slimming pills such as these. He said: 'If the ketones had not been so readily available, Cara might still be here today'
After taking two pills, Miss Reynolds went to her father complaining of heart palpitations.
He said: 'She'd only taken the recommended amount of pills but was scared because her heart was going 10 to the dozen.
'That's when she said she wasn't going to take them for weight loss any more - it had really worried her.'
But a month later, on March 5, 2013, she had a seizure.
Miss Reynolds admitted she had taken most of the slimming pills and was vomiting and fitting for half an hour before falling unconscious.
After finding his daughter unconscious on her bedroom floor, Mr Reynolds noticed evidence of raspberry ketones and called an ambulance.
He said: 'I held my only daughter in my arms and before she became unresponsive she kept telling me she had made a mistake and that she didn't want to die.
'She'd broken up with her fiance of one year and was left devastated by the rocky relationship.
'In a moment of madness, she'd taken an overdose because she had the ketones to hand.
'It was the most heart breaking moment of my life, and one I will never forget.'
When paramedics arrived to rush her to the Royal Infirmary, Edinburgh, he told medics he had found the empty packaging by her body.
Despite 44 attempts to resuscitate her, Miss Reynolds died five hours later from cardiovascular collapse because of the fatal dose of caffeine she had ingested.
A case report of her death submitted to the British Medical Journal (BMJ) said the high dosage of caffeine sent her heart into cardiac arrest.
The report author stated: 'This case report highlights the dangers of increasingly popular over-the-counter slimming pills.
'Many slimming products have concentrations of up to 250mg of caffeine per tablet which is equivalent to more than four cans of Red Bull or seven cans of Coca Cola.
Her family has now launched a campaign to make stores take the pills off their shelves.
Raspberry ketones are advertised on Boots' website as a natural, fruit extract to help with weight loss.
It is recommended that no more than four capsules are taken each day - the caffeine equivalent to 16 cans of energy drink.
Mr Reynolds added: 'These pills are dangerous and need to be taken down by retailers.
'There also need to be age restrictions imposed on the purchase of diet pills and so called safe weight loss pills alike.
'These pills are not herbal or harmless like most people are led to believe.'
As part of his campaign, he has written to the retailer informing them of his daughter's death and asking them to stop selling raspberry ketones.
A representative for Forza said: 'This is a tragic and understandably upsetting situation for her family and friends, but it could have been effected through the misuse of any supplement.
'Forza products meet vigorous health and safety standards and have clear labelling and directions for safe usage.
'It is regrettable to our client that an intentional overdose of a large number of capsules of a food supplement has potentially contributed to Miss Reynolds' suicide.
'The facts surrounding this incident are not yet wholly clear, but our client entirely rejects any implication that an inherent safety issue with its products is responsible.'