The subject of this article is an eight-page manuscript preserved in the Cairo Genizah (Ms. Cambridge T-S K14.14), which we identified as a fragment of a mid-15th century copy of Abraham Avigdor's Hebrew translation of Gerard de Solo's Practica super nono Almansoris. Besides the edition and translation of the fragment, we discuss the historical and textual background of Abraham Avigdor's work. A special focus of the article lies in the extensive use of Latin and, in particular, Old Occitan medical terminology in Avigdor's text, as evidenced in the fragment. This issue is discussed against the background of the Jewish-Christian contact and collaboration that took place in the medical centers of Southern France during the 14th century.