We studied 52 children, 3 to 15 years of age, suffering from allergic reactions following Hymenoptera stings. The diagnosis of allergy was based on history, results of skin tests and RAST performed by purified venoms of Apis mellifera, Vespula species and Polistes species. The history of children with multiple stings of the same insect showed an essential favourable prognosis, thus suggesting to submit to specific immunotherapy only children with severe reactions. For these patients it is necessary to perform therapy only in specialized Centres, because of the high frequency of adverse reactions which we observed in 33% of our treated patients.