At the a two-year apprenticeship, a young female hairdresser developed rhinoconjunctivitis and bronchial asthma, induced by a hair bleach containing the substance persulphate. On each occasion, her symptoms occurred in the form of an immediate reaction. The causative role of the bleach was demonstrated with the aid of an inhalation challenge test. In addition, the prick test produced a positive reaction vis-a-vis persulphate. The long latency period and the positive prick test might militate in favour of an allergic pathomechanism.