The lifetime prevalence of bronchial asthma in adults is approximately 5%. Recommended drug therapy of this condition depends largely on its severity and varies from the on demand use of bronchodilators as a single measure up to the additional and sometimes permanent use of inhaled and/or systemic glucocorticoids. In this study, the prevalence and drug therapy of bronchial asthma were analysed in a representative sample of the resident population in Germany aged 18-79 years. We also report about health care utilization, like hospital stay, emergency treatments and use of ambulant medical care, and its associations with asthma medication. Of those study participants who affirmed a medical diagnosis of asthma, 17.3% used corticoid drugs continuously, 19.1% occasionally and 61.8% never. Use of medical services after an asthma attack was reported most often by those who took corticoid drugs regularly. Older people with asthma mostly used glucocorticoids regularly, while in very young patients the occasional use of corticoids was reported more often. When looking at the actual drug use (7 days before the examination) according to the drug usage questionnaire, anti-asthma drugs were mentioned as follows: 47.8% of persons with asthma, diagnosed during the last 4 weeks, used inhaled adrenergic drugs, 34.8% inhaled glucocorticoids, 2.1% systemic adrenergic drugs and 19.3% systemic theophyllines. The measured serum concentrations of theophylline were below 5 mg/l in 34.4%, between 5 and 8 mg/l in 28.1%, between 8 and 20 mg/l in 35.9% and somewhat over 20 mg/l in 1.6%. Our data suggest that especially young asthmatics may not be sufficiently treated with anti-inflammatory therapy, but further studies are needed. If such a deficit can be confirmed, measures for better adherence of therapy to existing guidelines should be considered. Our results, especially on serum concentrations of theophylline, suggest that therapeutic drug monitoring (TDM) of serum samples is not only an important tool in health surveys, but also suitable for increasing the safety and quality of drug treatment in asthmatics.