Allergy is considered a large global problem. Incidence of allergic diseases is estimated to be 25% globally and about 20-40% in Norway. Allergen specific immunotherapy (SIT) has been used for over 100 years and is the only known therapy that potentially can cure this disease. The objective of the following thesis is to give a summary of this treatment, and to see if it is a treatment that still should be recommended for allergic patients in Norway. The methods used in this thesis are online searches in PubMed, references, curriculum and Norwegian Guidelines for Allergy Vaccination. Several meta-analysis and systematic reviews, have shown that SIT can be effective in reducing allergic symptoms and the need for additional medical therapy, compared to placebo. Side effects occur with SIT, from mild local irritation to severe anaphylaxis. But severe systemic side effects are uncommon when the Norwegian guidelines for vaccination are followed. It is estimated that 12-13.000 patients receive treatment with SIT in Norway today. The compliance in Norway is presumed to be high, but is a great problem globally. In conclusion: SIT can be an effective therapy for patients with allergic rhinitis against inhalant allergens. It is a safe therapy when the guidelines are followed, and should still be recommended for allergic patients in Norway. More awareness of this form of treatment should be emphasized in the Norwegian medical society. We are still in need of vaccines that are more effective, have less adverse effects and have shorter treatment durations. Finally we need more research in this area in the Norwegian population.