An open, crossover study lasting 8 weeks was performed to establish if a twice daily regimen of combined inhalation of salbutamol and beclomethasone dipropionate from a single inhaler was as effective in controlling asthma as the 4-times daily regimen. The results from these two treatment periods were compared with an initial 4-week baseline period when all patients received the same agents from separate inhalers on a 4-times daily dose schedule. Twenty stable asthmatics were entered into the study and 19 completed the three treatment periods. The clinic lung function data, symptomatic inhaler usage, requests for additional therapy and physician's subjective assessment of treatment showed that all three treatment regimens were similarly effective in managing the patients' asthma. There was no significant difference between the mean PEFR measurements taken 4 times each day between the two treatment regimens of the combination inhaler. However, except for PEFR in the afternoon, the mean values for both treatment schedules of the combination inhaler were significantly greater (p less than 0.05) than those during the separate inhaler baseline period. More than half the patients considered that both treatment schedules of the combination inhaler provided better control of their asthma than treatment with the separate inhalers, and the majority preferred the twice daily regimen to the 4-times daily regimen. The results, overall, showed that in stable asthmatics the combined administration of salbutamol and beclomethasone dipropionate from one inhaler provides significantly better therapy than the same agents from separate inhalers and that the twice daily dose schedule of the combination inhaler is equally as effective as a 4-times daily regimen.