Background: Because bronchial inflammation was recognized as a basic component of bronchial asthma, the strategy for asthma management has changed in the last two decades. In Japan there are few clinico-epidemiological reports of changes in the management of bronchial asthma in actual practice. In this study, we analyzed practical asthma management in Japan, and examined changes in the prevalence of asthma medication and relation between these changes and the level of asthma control and management. Methods: From 1998 to 2002, questionnaires on asthma control, asthma related emergent episodes and satisfaction in daily life. Questionnaires were distributed to adult asthmatic patients. Questionnaires about the patients' profiles and medication were also given to the patients' doctors. Results: The total number of patient responders was approximately 2500-3300 per year. The rate of peak flow meter (PEFM) use was under approximately only 40% and plateaued from 2000 to 2002. The percentage of inhaled corticosteroid use and leukotriene receptor antagonist use increased, from 62.0%, 27.2% to 77.4%, 40.6% respectively. Indicators for asthma control, including presence of attacks and sleep disturbance, were significantly improved. Limited to PEFM users, there was an improvement hospitalization, ambulance use or ED visits and in satisfaction in daily life based on a Quality of Life (QOL) indicator. Conclusions: These results indicate that the prevalence of anti-inflammatory agents, including inhaled corticosteroids and leukotriene receptor antagonist, was associated with an adequate improvement in asthma control in clinical practice. In asthma management in clinical practice, prevalence of PEFM may play an important role in the improvement of asthma related emergent episodes or QOL. ©2005 Japanese Society of Allergology.