Modern lawmaking in the field of pharmaceutical patents and surrounding regulation is to a considerable extent based on legal transplants. Legal transplantation contributes to international harmonisation without requiring an international convention, something very attractive for actors in the pharmaceutical sector operating on an international market. Despite its informal character, and alleged efficiency and simplicity in the transfer of legal rules from one jurisdiction to the other, it requires certain caution. A legal rule may very rarely be seen in complete isolation from the rest of the legal system, since in some cases it is not possible to foresee the results of the legal rule in the exporting country before the transplant takes place. In the field of pharmaceuticals, significant examples of legal transplants are the Bolar exemption and the Supplementary Protection Certificate, both transplanted to the EU by the same US Act, the Hatch-Waxman Act. This article evaluates these two legal rules, comparing their strengths and weaknesses to those of the original provisions in order to highlight different aspects of the process of legal transplantation and the effect they have on the formation of the transplanted rules.