In a double-blind, double-placebo, randomized crossover study, we compared the effects of 6 wk of treatment with the anti-inflammatory drug nedocromil sodium (16 mg/day) with 6 wk of treatment with the bronchodilator drug albuterol (800 micrograms/day) in 29 adults with allergic asthma. After 3 and 6 wk of treatment with nedocromil sodium, patients were significantly less hyperresponsive to propranolol (p = 0.002 and p = 0.02) and almost significantly less hyperresponsive to histamine (p = 0.071 and p = 0.065). FEV1 and FVC percent predicted tended to be higher, morning PEF values increased significantly (p = 0.038 and p = 0.03), and diurnal and day-to-day PEF variation decreased (p = 0.03 and p = 0.093, p = 0.005 and p = 0.096, respectively) with nedocromil sodium treatment compared with albuterol treatment. Almost all symptoms (daytime and nighttime asthma, wheezing, shortness of breath) and the additional bronchodilator use were significantly reduced with nedocromil sodium treatment compared with albuterol treatment. Treatment with the anti-inflammatory drug nedocromil sodium was shown to be superior to treatment with the bronchodilator drug albuterol. The patient's clinical situation may deteriorate when beta 2-agonists are used continuously. Nedocromil sodium has good clinical effect, and it may serve as a first-line choice for antiinflammatory therapy in asthma.