By Gabriella Zuccolin Yarrow. From Dioscorides, De medicinali materia.Credit: Wellcome Library, London. Before starting my research on anomalous bleeding and vicarious menstruation in medieval and Renaissance medicine, I was already well aware that according to Hippocrates, Aphorism V.33, “in a woman when there is a stoppage the menses, a discharge of blood from the nose is good”. What I did not know then is that the absence or irregular flow of menstruation puzzled physicians and their pati...