The Royal Pharmaceutical Society has told ITV News that people buying so-called diet pills online are "playing Russian Roulette with their life".
In an interview, pharmacist Neil Patel said:
"If you buy diet pills online you are playing Russian Roulette with your life.
You are actually buying products that have been banned in the UK because they cause serious life threatening side-effects such as heart attacks and strokes."
The mother of Eloise Parry, who died after taking DNP, appeals to others not to make the same 'bad choice' that cost her daughter's life.
An ITV News investigation revealed banned drugs with potentially lethal side effects - and even heroin - are freely available online.