There are only few human translational studies performed in the area of stem cell research in patients with chronic obstructive pulmonary disease (COPD) and/or pulmonary emphysema. Before progress to clinical trials with stem cells we strongly believe that more human translational studies are essential, otherwise, the clinical rationale would be solely based on limited in vitro and animal studies. In the future, stem cell therapy could be a treatment for this incurable disease. As of now, stem cell therapy is still to be considered as an area of active research, lacking any strong rationale for performing clinical trials in COPD. Although stem cells would be likely to represent a heterogeneous population of cells, the different cell subsets and their importance in the pathogenesis of the different clinical phenotypes need to be fully characterised before progressing to clinical trials. Moreover, the potential side effects of stem cell therapy are underestimated. We should not ignore that some of the most deadly neoplasms are arising from stem cells.