Opinion statement Allergen-specific immunotherapy is the only treatment able to change the natural history of either respiratory or hymenoptera venom allergy. From an immunological point of view, there is no reason to believe that its clinical effects should be different in food allergies. However, due to the high prevalence of adverse events that accompanied the first attempts of injection immunotherapy with food extracts some 20 years ago, such treatment is presently non-available although a thoroughly standardized food extract for injection immunotherapy should theoretically not expose the patients to higher risks than airborne allergen extracts or venoms. Allergen-specific immunotherapy with birch pollen extract is an interesting model to investigate the effects of the treatm...