Current research on allergen immunotherapy (AIT) includes several directions as: new indications, new routes of administration, therapeutic preparations containing modified allergens, recombinants, peptides, new formulations and adjuvants as well as vaccine carriers, and a combination with potential immunomodulators (e.g., Vit. D3) and biological therapies. Studies are focused on understanding the mechanisms of effective AIT, improving patient selection and better diagnostics of allergies (molecular diagnostics). The new routes of administration include the administration of allergens into lymph nodes, as well as epidermal and intradermal administration. Analysis of the effectiveness of AIT is ongoing in atopic dermatitis and potential methods of tolerance induction in food allergies are extensively studied. In research monophosphoryl lipid A (MPL A), CpG enterotoxin motifs and muramyl dipeptide are used as new adjuvants. The effectiveness of probiotics (Lactobacillus rhamnosus LGG), proteins of viral capsids (VLPs) and immunostimulatory complexes was analyzed. New methods for binding and administration of allergens, e.g. using nanoparticles or liposomes are studied. Further work is ongoing looking for the optimal methods to assess the effects of AIT, including new, reliable biomarkers. The primary goals of these studies are to improve the effectiveness of AIT, including long-term modification of the course of the allergic disease, reducing the number of administrations of subsequent doses, with the most optimal safety profile of allergen immunotherapy.