This article explores the significance of the medical discourse of hysteria, pathological sexuality and mental imbalance in Rachilde's works. The departure point is the hysterical attack she suffered about 1882, complicated by paralysis, and her treatment by the famous hysteria and paralysis specialist, Dr. Charles Lasègue. I trace the evolution in her works of the figure of leglessness as sexual renunciation/sexual perversion and argue that La Marquise de Sade contains a story of inherited physical and sexual abnormality with masked references to Drs. Blanche and Lasègue and to the deranged mass murderer Jean-Baptiste Troppmann. The article demonstrates how Rachilde's early sense of "writing as malady" was overtaken by the understanding that dreams and the unconscious could be a valid source of creativity (MRF).