Abstract.Objective. Allergic rhinitis (AR) is a disease with high and increasing prevalence. The management of AR includes allergen avoidance, anti-allergic drugs, and allergen specific immunotherapy (AIT), but only the latter works on the causes of allergy and, due to its mechanisms of action, modifies the natural history of the disease. Sublingual immunotherapy (SLIT) was proposed in the 1990s as an option to traditional, subcutaneous immunotherapy. Material and methods. We reviewed all the available controlled trials on the efficacy and safety of SLIT. Results and conclusion. Thus far, more than 60 trials, globally evaluated in 6 meta-analyses, showed that SLIT is an effective and safe treatment for AR. However, it must be noted that to expect clinical efficacy in the current practice SLIT has to be performed following the indications from controlled trials, that is, sufficiently high doses to be regularly administered for at least 3 consecutive years.