Bronchiolitis obliterans syndrome is the major cause of mortality after lung transplantation. 5 years after lung transplantation about 50% of all patients have this syndrome. There are nearly none therapy options. Besides effective therapy of any gastrooesophageal reflux and an oral medication with azithromycin none further regimens are known. Photopheresis could show in several studies a benefit for patients with gvhd after bone marrow transplantation or for chronic rejection after any other solid organ transplantation. Just little case reports could show beneficial effect in patients with bos after lung transplantation.