This book is a shorter version of a doctoral thesis realized under the direction of Robert Delort on the scientific work of Hildegard of Bingen (1098-1179). And discussed in 1994. The medical rules of the German nun, which the public rediscovers today enthusiastically, are kept in late manuscripts, susceptible to have undergone a lot of modifications, and raise many questions. The medical writings which she conceived and drafted are they really those who reached us? In 1533, the printer Jean Schott in Strasbourg gave an editio princeps under the title of Physica, stranger to all known manuscripts : was it established according to a witness today disappeared, or did the editor proceed to reorganizations and interventions on the original work...