The strange object labelled 'Lapis Bezoar ex Iguana' rests today in the reassembled cabinet of medicinal curiosities that was kept for centuries in the back room (rebotica) of the Salvador family apothecary in Barcelona, Spain. What is this strange object doing here? And what can it tell us about the place of New World objects in the global history of collecting and medicine? This particular object, and indeed all those called bezoars, was believed to possess medicinal powers. But by what criteria was this bezoar stone placed in the reserved cabinet or rebotica collection rather than on the open, commercial shelves of the apothecary? Where was the line drawn between the marvellous or curious object and the commercial commodity that could be readily sold as medicine in the dispensary? This line reflects both the presentation and disenchantment of nature that followed from the first globalisation, while the ex-iguana bezoar stone registers the ambiguities of authenticity in the Indies. In truth, there was no fixed line between the marvellous and the mundane, or indeed between the authentic and the fake; instead, there was a continuous movement, re"ecting the changing state of knowledge, geopolitical realities and the private interests of those who curated the collection and ran the apothecary.