Inflammation is a hallmark of bronchial asthma. Inflammatory cells both in bronchoalveolar lavage (BAL) and bronchial biopsies of asthmatic patients have been studied and correlated with functional or clinical parameters. We have recently attempted to assess airway inflammation by a visual endoscopic scoring system. The purpose of this study was to compare our own endoscopic scoring system with the bronchitis index previously described by Thompson and coworkers, and to determine whether these scores were correlated with clinical or functional parameters. Sixty asthmatics of variable severity (forced expiratory volume in one second (FEV1) 33-117% of predicted values) and 30 healthy volunteers were studied. The clinical severity of asthma was assessed by the clinical score as described by Aas in all of the patients, and in the last 15 patients by a daily symptom score. Beta 2-agonist consumption was recorded daily during a period of 7 days before the endoscopic procedure. During this period, circadian variation and day-to-day variation of peak expiratory flow rate (PEFR) were determined. During bronchoscopy, airway inflammation was assessed by two independent observers, prior to BAL, by visual inspection of each lobe and the lingula, and the results were quantitated using the bronchitis index and our endoscopic scoring system. Both endoscopic scores were significantly higher in asthmatics than in controls. A significant correlation was observed between the two endoscopic scores both in asthmatics and in controls. In asthmatics, a weak but significant correlation was found between both endoscopic scores and the daily symptom score, as well as the beta 2-agonist consumption.(ABSTRACT TRUNCATED AT 250 WORDS)