We made the observations that in patients with severe bronchial asthma, the inhalative dose of beta-2 sympathomimetics that was required for optimal bronchial dilation revealed a large inter-individual scatter. In 21 patients, the inhalation of a maximum of 10 metered doses of salbutamol at intervals of five minutes each, led to a mean (SD) increase in the FEV 1.0 from 1.3 (0.6) 1 to 1.8 (0.7) 1. The maximum increase in the FEV 1.0 was achieved in 10 patients following the inhalation of 1 to 3 metered doses, and in 11 patients after 4 to 10 such doses. The individual requirement for inhaleable beta-2 agonists should therefore be taken into account when planning treatment.