The "Spanish Flu" began in 1918 and was the most devastating pandemic in human history that had ever been, claiming more lives than World War I. The flu virus had not yet been discovered, and the usual therapy measures were merely symptomatic. In many parts of the world the pandemic was treated by homeopaths. At the time, homeopathic medical practices, out-patient clinics and hospitals existed in various countries. To this day homeopaths refer to the successful homeopathic treatment of the "Spanish Flu". The following paper looks at what this treatment consisted in and whether it was based on a particular concept. It also examines contemporary evaluations and figures, as well as the question as to whether homeopathy experienced a rise in demand as a consequence of its success during the pandemic.