Emile Zola is one of the greatest writers in universal literature. In his important series of novels called "The Fortune of the Rougon-Macquart", Zola shows a surprising medical knowledge even though he did not have a formal medical education. We highlight not only his outstanding literary talent, but also the scientific relevance of the tremendous contribution to the medical field that can be extracted from his work. In this series, which describe the history of five generations within a large family suffering from neuropsychiatric and general pathologies, Zola emphasizes the hereditary component of several diseases. These observations probably place him as the first novelist who made an explicit emphasis on the power of inheritance in human behavior. He also mentions for the first time several medical aspects that were seldom addressed in the scientific literature of the time, demonstrating the genius of the writer, his outstanding power of observation and the rigorous preparation with which he wrote his work.