Allergen immunotherapy (AIT) is the only causal therapy for allergic diseases and therefore particularly important. Allergen preparations are classified as medicinal products since 1989 (Directive 89/342/EEC) and were taken over into Directive 2001/83/ EC in 2001. In addition, in 2008 the Therapy Allergen Ordinance (TAO) came into force to stricter regulate the exception for named patients products (NPP) by exclusion of common therapy allergens from the exception to be marketed as NPP. The TAO regulates the requirements for testing safety and efficacy for these common therapy allergens. Due to the long transitional provisions the last deadlines for solving clinical shortcomings will end in 2026. The advantage of this regulation is that the market for common allergens has been cleared of products without proof of efficacy, and new preparations with an optimal dose range are developed through dose-finding studies. The demand for long-term paediatric studies has been outlined by the standard Pediatric Investigation Plan (PIP) on allergen products from the paediatric committee of the EMA (PDCO). This is particularly problematic, as it is foreseeable, that recruitment of patients will be limited and ethical problems arise from the prolonged use of placebo. Furthermore, many newly approved preparations will not be used in paediatrics for the foreseeable future, as no marketing authorisation has yet been granted for this age group. This will result in a serious supply gap for children.