The Swiss Society for Clinical Pharmacology and Toxicology recommends that off-label drug therapy should best be carried out in the framework of a clinical study. This enables that the (positive and negative) results and outcomes can be evaluated scientifically and can lead to a progress in patient care and science. Clinical studies with experimental therapies should be planned and carried out with control groups, since without control groups receiving standard of care it is not possible to estimate the benefits (and risks) of the experimental drug therapy.