Allergic diseases such as asthma, atopic dermatitis, rhinitis and urticaria are immunological disorders affecting almost one third of the population in industrialised countries. Therapeutic or prophylactic approaches to turn around the increasing prevalence of these diseases have been intensively investigated. Allergen-specific immunotherapy has been applied in clinical practice for many decades, although varying results and occasional severe side effects have called for more effective and safer vaccines. Recent advances in our knowledge of immunological mechanisms have created several options to comply with these demands. This article will focus on some of the most promising new developments.