Objectives : The purpose of this study was to develop outcome indicators in clinical trials of herbal drugs effective for asthma. cough and sputum. To accomplish the objective, this study collected outcome indicators developed and used according to conventional medical concepts. Methods : Our research group reviewed SCI papers concerned with developing outcome indicators to evaluate amelioration of asthma, cough and sputum. We also reviewed clinical trials of herbal drugs effective for them. Results : To evaluate asthma, objective as well as subjective methods were chosen according to the purpose of each trial. Objective methods were PEF, FEVl, serum IgE, peripheral eosinophil counts, and so on. Subjective methods were symptom scores, symptom diaries, quality of life measures, etc. To evaluate cough and sputum, objective and subjective methods were also chosen. Objective methods were tussigenic challenges, sputum induction and computerized methodology, and subjective methods were similar to the methodology evaluating asthmatic symptoms. Conclusions : It is desirable for a clinical trial evaluating herbal drugs for asthma, cough and sputum to use objective and subjective outcome indicators together. However, biological outcome indicators, a kind of objective methods, can not be chosen as the purpose of trial. Valid and reliable subjective outcome indicators are needed to develop good clinical trials of herbal drugs effective for asthma, cough and sputum.