We present 10 cases (6 males and 4 females) of children aged 4 to 12 years, who were diagnosed with allergy to clavulanic acid (CL) and treated in the Paediatric Allergy Section of the University Hospital Dr. Peset in Valencia from 2000 to 2005. The children reported symptoms of urticaria and angio-oedema after receiving orally-administered amoxicillin/clavulanic acid (A-CL) for an infection. Diagnosis was based on the confirmation of an IgE-mediated aetiology by an oral challenge test with amoxicillin-clavulanic acid. Following negative skin test results and CAP for penicilloyl G and V, amoxicillin, ampicillin and cefaclor < 0.35 KU/l, those patients who were allergic to clavulanic acid (positive oral challenge test) were shown to be tolerant to orally-administered Cefuroxime axetil.