A young Irishman has died after taking slimming products purchased online.
The man, who is in his mid-20s, has not been identified and died in May, according to the Health Products Regulatory Authority (HPRA).
The fat-burning product he took contained a highly-toxic substance marketed as a "wonder slimming aid".
The HPRA issued a fresh warning following the recent death which occurred after the suspected consumption of a product that contained Dinitrophenol (DNP).
The authority is now liaising with gardai who are investigating the supply of DNP products and the events surrounding the man's death.
"These investigations are on-going, and we strongly urge members of the public to never use the internet to source slimming products or any prescription medicines at any time - no amount of these products is safe to take," said Pat O'Mahony, Chief Executive of the HPRA.
"Bogus websites can be very sophisticated and appear to be legitimate. However, in reality, they can be supplying unsafe and harmful products."
To date, a small number of tablets containing DNP have been detained by the HPRA.
However, as the internet is an unregulated source of supply of slimming products and other medicines, the HPRA is concerned that products containing this substance may have been purchased by Irish consumers.
DNP, an industrial chemical popular with some bodybuilders trying to lose weight, has been linked to over 60 deaths worldwide, but this is the first reported case in Ireland.
Following the death of a woman in the United Kingdom linked to DNP, Irish authorities warned that products containing DNP were "not fit for human consumption and have the potential to cause serious harm."
It advises consumers, as it has done in the past, not to purchase any slimming products which may be illegally available online, and to contact their doctor immediately if they have taken a product containing DNP and feel unwell. The HPRA have seized 93 tablets containing DNP so far this year.
Anyone with information can contact the HPRA by e-mail on firstname.lastname@example.org or by phone at 01 634 3436.
Further information about the dangers of buying medicines online is available on www.hpra.ie