Norwegian researchers analysed two dietary supplements that the manufacturers claimed to be natural, highly fat-burning and energising. Urine and serum samples from six individuals taking these supplements were also analysed. Serum analyses showed diazepam, clonazepam, ephedrine and metabolites after intake of the dietary supplement Thermo-X 650, and ephedrine and phenylpropanolamine after intake of the supplement Purple Burn. The authors warn of the potentially serious consequences of incomplete content declaration, for instance through interactions with drug therapy, and request that consumers must be given sufficient product information for safe use.