Tradition and Medicine on the Wings of a Fly

This study examines the pre-modern debate surrounding a strange Islamic prophetic tradition (hadīt) that commands to fully immerse a fly that has fallen into a drink, "for in one of its wings there is poison and in the other a cure". Studying different discussions of the hadith from the 3th/9th to the 9th/15th centuries reveals the variety of ways Muslim scholars negotiated the substantial tension between the competing authorities of prophetic tradition and the Greco-Islamic scientific tradition. Finally, I propose a possible explanation for the idea of a poison and cure on flies' wings in Greco-Roman medical discussions of the Spanish fly.