Acute exacerbations of COPD have a broad range of effects on the patients in addition to cough and sputum production. These include malaise, increased dyspnea, diminished tolerance and social restriction. No single clinical or physiological measure captures this multiplicity of effects adequately. Health status measurement using instruments erroneously termed ;quality of life' questionnaires can provide this integrative function. Validation studies have shown that these scores reflect exercise capacity, respiratory symptoms, disability in daily life, and impaired mood. Furthermore they relate to levels of arterial hypoxaemia in COPD and blood leucocyte count in patients with bronchiectasis. Health status scores have been shown to predict hospital readmission or death in patients with COPD. Recent studies have shown that whilst sputum color and volume recover within a week of starting treatment, full recovery of health status may take over three months. This is consistent with the observation that exacerbation frequency is strongly related to health status and a recent report that the rate of decline in health status over time is related to the frequency of exacerbations. Health status instruments were developed originally to measure treatment efficacy, but they also provide insights into acute exacerbations of COPD and their clinical importance.