To study the effect of different schedules of allergen administration on the early (EAR) and late allergic reaction (LAR), 15 asthmatic patients with dual response after allergen challenge were submitted to two consecutive bronchoprovocation tests (BPT). BPT1 was carried out with semilogarithmic increases of allergen doses until a FEV1 drop of 20% was recorded. BPT2 was performed 2 weeks later using the highest allergen dose that had elicited the dual reaction in BPT1. Both EAR and LAR were very similar for a given patient. As the allergen dose used in BPT2 is smaller than the cumulative allergen dose administered in BPT1, this protocol takes into account a possible influence on BPT2 of bronchial hyperreactivity induced by BPT1 performed 2 weeks before.