In children treated with beta-lactam antibiotics (BL), the majority of presumed allergic reactions are not due to drug hypersensitivity (HS), but rather to infectious diseases. As a result, the oral provocation test (OPT) for LAB has found its place in 1st-line allergological investigation. The aim of our work was to describe the procedures for reintroduction testing with LAB and to demonstrate the contribution of oral provocation testing with LAB as a 1st-line test in the positive diagnosis of LAB allergy.