The paper reports 5 cases of bronchial asthma in hairdressers exposed to bleaching dusts containing potassium and ammonium persulphate. All subjects complained of asthmatic symptoms at diagnosis, and underwent measurement of non-specific bronchial hyperresponsiveness to methacholine, skin prick tests for common allergens, PEF monitoring during 2 weeks at work, specific bronchial challenge (SBC) test with bleaching dust, and assessment of airway inflammation by induced sputum technique. All subjects were reassessed during a follow-up of 1 to 5 years. All subjects were negative for skin prick tests, but 3 showed an abnormal PEF variability at work (Maximal Amplitude > 10%, in at least half of the monitoring period). All subjects showed a positive airway response to SBC with bleaching dust, and 4 subjects did not react to the control tests with lactose dust. One subject only showed a high percentage of eosinophils (> 3%) in the induced sputum, while all were hyperreactive to methacholine (PD20FEV1 < 0.3 mg). During the follow-up, 2 subjects stopped working and 4 were treated by inhaled corticosteroids and bronchodilators. All subjects reported a significant improvement in asthmatic symptoms, related partly to the reduction of occupational exposure in the workplace and to the efficacy of anti-inflammatory treatment. In conclusion, similar findings were observed in these 5 cases of hairdresser asthma: absence of atopy, positive response to SBC, mild changes in PEF and variable percentages of eosinophils in induced sputum. Pharmacological treatment, associated with reduction of occupational exposure, could improve asthmatic symptoms, despite continuing the job.