Appropriate specific immunotherapy depends on the correct diagnosis, identification of the clinically relevant allergens and consideration of risks. Standardized high-quality allergen extracts preferably of known major allergen content and with clear-cut proven efficacy in randomized controlled studies should be used for both SCIT and SLIT. The various SCIT and SLIT extracts differ considerably, so an allergen and product specific evaluation is recommended for the respective choice and indication. The German allergy society's comparison of SLIT to SCIT is much less favorable than that of the European society. In the absence of high-quality direct comparisons between the two therapies, a high-quality SCIT should be preferred to SLIT because long-term and preventive effects (development of asthma and new sensitizations) have been demonstrated more satisfactorily for SCIT. If SCIT is out of the question (refusal of injections, systemic side effects of SCIT) a high-quality SLIT may be indicated in adults with rhinoconjunctivitis.