The current COVID-19 (coronavirus disease 2019) epidemic has proved challenging due to its high impact on physical and mental health. According to Hahnemann, the founder of homeopathy, in an epidemic the most severe symptoms of the clinical condition presented by the population in question should be the basis for selecting the medication that is as similar as possible to them, and which should be administered to individuals who have been exposed to the disease but have not yet developed it. This medicine is called the genus epidemicus. This study aims to demonstrate the reasoning used to propose the homeopathic medicine Antimonium tartaricum (Ant-t) as a genus epidemicus in the COVID-19 epidemic. It was decided to develop the reasoning based on the respiratory symptoms described in the epidemiological bulletins presented by the Health Surveillance Secretariat of the Ministry of Health of Brazil, as these symptoms are the most serious of the disease. After repertorization, it was confirmed in the Materia Medica that Ant-t has a high degree of similarity with these respiratory symptoms, including the most serious situations, of COVID-19. Homeopathic Ant-t is thus a possible prophylactic genus epidemicus in the COVID-19 epidemic; further studies are needed to test this conclusion.