Guidelines and recommendations of European and Polish scientific societies and expert groups do not have legal nature, but as they are based on current medical knowledge and created in line with the evidence based medicine (EBM), they provide useful guidance in everyday clinical practice. According to the European Parliament’s directives, allergens used in diagnostics were included into the group of allergenic products, and allergenic products have become immunological medicinal products that are subject to mandatory registration before being placed on the European Union market. European Medicines Agency (EMA) introduced new quality requirements for allergen products and precisely defined requirements for clinical trials for specific immunotherapy. As a consequence those regulations led to temporary breaks in the distribution of some allergen products, withdrawals from the market of another diagnostic and therapeutic allergens, interruptions of some clinical trial projects, and significant extension of the time necessary for registration of new vaccines. Polish legal regulations impose on medical personnel the obligation to inform and collect informed consent from the patient before application of any diagnostic and therapeutic procedures. The Pharmaceutical Law and the Regulation of the European Parliament and the Council of the European Union on the activities related to pharmacovigilance, impose an obligation to notify authorities on adverse reactions of any medicinal products, including those used in diagnostic procedures and for allergen immunotherapy.