Nedocromil sodium is a pyranoquinoline dicarboxylic acid derivative, formulated in a metered-dose inhaler. Because nedocromil sodium has in vitro and in vivo anti-inflammatory properties, it was evaluated in a group of steroid-dependent patients with asthma to observe how well it might be tolerated and for evidence of any beneficial effects. In a double-blind, group-comparative study, 127 patients received nedocromil sodium and 61 received placebo, administered as two puffs of 2 mg, four times per day, for 12 weeks. Ten patients developed adverse reactions, seven receiving active drug and three patients receiving placebo. Two patients of each group withdrew because of worsening asthma. Despite selecting patients whose asthma was stable, when they were receiving established therapeutic regimens that included steroids and bronchodilators, it was found that diary-card symptom scores, morning and evening peak expiratory flow rate values, and inhaled beta-agonist usage all demonstrated slight but significant benefit with addition of nedocromil sodium. It is concluded that the inhaled, anti-inflammatory agent, nedocromil sodium, may be added to asthma-treatment regimens with the reasonable expectation of further modest symptomatic benefit.