Professional use of topical treatment in dermatological practice requires not only knowledge about the pharmacological properties, efficacy, safety and pharmaceutical quality of a preparation, but also about its regulatory classification. The latter essentially determines the physician's prescription practice and therapeutic freedom. The regulatory framework with which one is confronted unfortunately lacks transparency. It regulates not only the prescribability and reimbursability of proprietary medicinal products and extemporaneous preparations, but also the obligation to give information as well as the details of liability of both the prescriber (physician) and the manufacturer (pharmaceutical company or pharmacist). The prescriber needs to be aware of to what extent the pharmacist has the possibility and even obligation to change the prescribed preparation. In some cases this can directly affect the therapeutic concept of the physician and even impair the effectiveness and safety of the chosen therapy.