While in Switzerland long-term home oxygen therapy has had little appeal in the management of patients with advanced chronic obstructive pulmonary diseases, hypoxemia, cor pulmonale and secondary polycythemia, it has been part of the therapy program in the USA and Great Britain for the last twenty years. Results from two controlled studies in those countries, showing a reduction of mortality in selected patients under long-term oxygen therapy, and the guidelines recently published by the Swiss Society of Pulmonology, justify an appraisal of our own situation. The pathophysiological basics are presented and the requirements and indications for long-term home oxygen therapy are outlined. The two controlled studies are summarized and commented on, and finally the practical application of this therapy in the Canton of Zürich is critically reviewed. Unsolved questions still exist with regard to the indication for its use, the unknown late complications, the considerable costs, and the inconvenient treatment period of 15 hours a day over a period of months, as well as the principal question, that of whether such therapy merely prolongs chronic suffering. These factors oblige us to maintain our reserved attitude about the use of this therapy and to employ it only after all the advantages and drawbacks have been carefully considered.