Consumers, and in particular body builders, have been warned by the Food Safety Authority of Ireland not to take "fat burner" capsules sold over the Internet as they posed a serious health risk.
The FSAI also cautioned consumers to stop using the Internet to buy these types of products.
The "fat burner" capsules contained an industrial chemical which was known to have serious health effects on humans if consumed, the FSAI said.
It advised the public not to consume "fat burner" products which contained dangerous 2, 4-Dinitrophenol (DNP) and to read labels carefully for identification of these chemicals.
DNP posed a serious health risk since it seriously disturbed the body's energy production at the cellular level and was considered to have high acute toxicity.
"Long-term oral exposure has resulted in the formation of cataracts and skin lesions and has caused effects on the bone marrow, central nervous system and cardiovascular system. It is used mainly as a pesticide and in purifying wastewater.
"The symptoms of exposure are nausea, vomiting, sweating, dizziness, headaches, loss of weight and may result in death," the FSAI said in a statement.
The Finnish National Food Agency tested the capsules after a Finnish body-builder who had taken them was hospitalised. The capsules were found to contain up to 380 mg of DNP.
The FSAI warned consumers to be very cautious about where they buy food supplements.
Mr Alan Reilly, FSAI deputy chief executive, said: "Consumers should only purchase products from reputable suppliers. Many Internet sites can offer a vast range of products, some of which would require product authorisations or approvals to be marketed in Ireland. However, as they are being sold over the Internet they are operating outside of these controls."