The tablets with the label "2 Day Diet" have been found to contain an active ingredient called sibutramine, which is a prescription-controlled medicine used as part of weight-loss treatments.
The Medicines Board has issued a warning to the general public, along with traditional Chinese medicine practitioners and suppliers and retailers of traditional Chinese medical products, about the pills.
The pills come in a plastic tub, which features white text on a red and white label. The pill bottle has a mushroom graphic and the words "slimming formula", "fat burner", "expelling of toxin" and "relieving constipation".
The bottle, with a screw-off security lid, contains roughly 60 purple capsules with no distinguishing markings.
It says the ingredients include "Ling Zhi, Ebony, Fox Nut, Tuckahoe, Seman Pruni, Dioscoreae, Wheat Germ and Nature Substance".
According to the IMB, "this product [2 Day Diet Capsule] is an illegal medicinal product which has not been authorised for marketing in Ireland and cannot be considered as suitable for consumption due to potential safety concerns".
Anyone taking the pills is advised to stop immediately and to consult their pharmacist or doctor. The IMB has a warning notice on its website (www.imb.ie) and it is suggested that anyone using the pills should take a copy of the IMB notice with them to the pharmacy.
The Board has also appealed to retailers and suppliers of the product to take the stocks off their shelves and immediately quarantine the product.
It has asked them to contact customers, where possible, to warn them of the dangers.