The homeopathic medicine Ferrum sidereum, coming from meteoritic iron, has been explored in two recent pathogenetic trials. The study of the provers’ testimonies, together with existing scientific knowledge about iron meteorites have led to a pathogenetic hypothesis on the indications for this medicine. With a first clinical confirmation, this hypothesis begins to find its legitimacy and we can shed some light on the possible use of this still little-known homeopathic medicine.