A search was performed to identify all relevant published clinical trials that addressed the effects of cardioselective β-blockers on airway function in patients with reactive airway disease. Two investigators jointly developed strategies with the help of an information service librarian and the Cochrane Airways Group Trial Search Coordinator. The EMBASE, MEDLINE, and CINAHL databases were searched comprehensively to identify all relevant clinical trials in humans published between 1966 and May 2001. The search was performed by using the Cochrane Airways Group registry to identify randomized, blinded, placebo-controlled trials of reactive airways disease. Terms used in the search were asthma *, bronchial hyperreactivity *, respiratory sounds *, wheez *, obstructive lung disease * and obstructive airway disease *. Trials of β-blockers were sought by using the terms adrenergic antagonist *, sympatholytic * and adrenergic receptor block *. Trials were not excluded on the basis of language. The search was further augmented by scanning references of identified articles, reviews, and abstracts at clinical symposia.