This article presents a plethora of fragments from the medical notebooks found in the Cairo Genizah that comprise a unique source of historical data for scholarly study and for a better understanding of the ways in which medieval medical knowledge in Egypt was transferred from theory to practice and vice versa. These documents provide the most direct evidence we have for preferred practical medical recipes because they record the choices of medical practitioners in medieval Cairo. Since the language most commonly used in them was Judaeo-Arabic, they were evidently written by Jews. The medical genre in the notebooks was primarily pharmacopoeic, consisting of apparently original recipes for the treatment of various diseases. There are also a few notebooks on materia medica. The subject matter of the Genizah medical notebooks shows that they were mostly of an eclectic nature, i.e. the writers had probably learnt about these treatments and recipes from their teachers, applied them at the hospitals where they worked or copied them from the books they read. Foremost among the subjects dealt with were eye diseases, followed by skin diseases, coughs and colds, dentistry and oral hygiene, and gynaecological conditions. The writers of the Genizah notebooks apparently recorded the practical medical knowledge they wished to preserve for their future use as amateur physicians, students, traditional healers or professional practitioners.