Chest physiotherapy is a treatment program that attempts to compensate for impaired mucociliary clearance. By removing mucopurulent secretions, it reduces airway obstruction and its consequences, such as atelectasis and hyperinflation; furthermore, physiotherapy can decrease the rate of proteolytic tissue damage by removing infected secretions. Conventional physiotherapy (clapping, vibration and compression, together with postural drainage and assisted coughing) is the most efficient physiotherapy for sick infants and young children. Later, mechanical chest percussion can reduce the patient's dependency on others. The forced expiration technique is another method of self-treatment, employing expiratory techniques to blow secretions out of the bronchi. Autogenic drainage, a special breathing technique, aims at avoiding airway compression by reducing positive expiratory transthoracic pressure. PEP-mask-physiotherapy achieves the same goal by expiring against an external airflow obstruction. Last but not least, physical exercise can clear the lungs of some CF patients and thus offers an attractive adjunct to physiotherapy.