The purpose of our study was to perform a meta-analysis and thus, based on original randomized placebo-controlled studies, evaluate the effectiveness and safety of sublingual immunotherapy (SLIT) in children and adults suffering from allergic bronchial asthma and rhinitis. On the MEDLINE, EMBASE, LILACS and SCOPUS web pages, the corresponding experimental works were searched. After an expert evaluation, 58 case-studies were selected 38. Of these, 30 concerned the efficacy and safety of sublingual immunotherapy of allergic rhinitis, and 8 of bronchial asthma. In active groups, 347 patients with asthma and 1888 rhinitis were involved, and in the control groups, respectively, 332 and 1795 subjects studied. There were 7 different meta-analytical comparisons based on the purpose of our study. Our Meta-analytic study on the selected publications have been shown that sublingual immunotherapy in children and adults suffering from allergic bronchial asthma and rhinitis is effective and safe. However, based on the low evidentiary level and high heterogeneity of the publication that we used in the meta-analysis, unambiguous recommendations regarding the advisability of using the sublingual immunotherapy method in patients with allergic rhinitis and asthma are premature. For all these reasons, the results of this analysis should be interpreted by the various selected population subgroups, following specific recommendations addressed to unified results, endpoints, time points, measurement scales and dosages, treatment distribution and power calculation. Despite our results, we believe that there are arguments indicating that SLIT may be a promising direction in the treatment of allergic rhinitis and asthma, but it should not be prescribed regularly to all patients.