Airway inflammation is consistently present in patients with severe asthma. The combination of inhaled steroids and bronchodilators may be useful both for treating symptoms and improving the underlying inflammatory condition. We have compared the effect of beclomethasone dipropionate (BDP) combined with salbutamol (S), BDP alone, and placebo, on the severity of bronchial responsiveness in 30 children with allergic asthma during the period of specific allergen exposure. In children treated with BDP alone, PC20-FEV1 methacholine was 0.66 +/- 0.54 at the beginning and 1.91 +/- 2.11 at the end of the study period (p greater than 0.05). In children treated with BDP + S PC20, methacholine was 1.21 +/- 1.43 at the beginning and 4.22 +/- 3.88 at the end of the study (p less than 0.05). The group of children treated with placebo had a PC20-FEV1 methacholine of 0.79 +/- 0.61 at the beginning of the study and 0.80 +/- 0.46 at the end of the study. The results of the present study show that maintenance treatment with inhaled beclomethasone combined with salbutamol may lead to greater improvement in bronchial hyperreactivity than treatment with inhaled beclomethasone dipropionate alone.