The sublingual route of administration of allergen (SLIT) has emerged as an effective treatment. Other non-injective route of administration of vaccines failed their goals; oral immunotherapy (OIT), local nasal immunotherapy (LNIT), local bronchial immunotherapy (LBIT) were reported as too expensive or unsafe or ineffective. Oral regimens were used in the first half of the 20th century but then they lost ground to injection immunotherapy. SLIT is suitable for home treatment and it has not to be regarded not only as a substitute of subcutaneous immunotherapy (SCIT), but also as a complementary or additional therapeutic tool in conventional medical practice. Currently, the balance sheet for SLIT is improving: with the steadily increasing number of patients with IgE mediated disorders, looking for a "cheap, safe and effective therapy" becomes a priority.