[Expectoration--an underestimated symptom?].

The prognostic value of pulmonary mucus hypersecretion is reviewed and is found to be considerable as regards COPD-mortality, -morbidity, and respiratory cancer. In contrast to previous belief, mucus hypersecretion cannot be considered a "harmless" respiratory symptom. The most efficacious intervention seems to be cessation of smoking, whereas little evidence is available supporting the benefit of long-term medical treatment or treatment involving chest physiotherapy.