This article presents an overview of the main questions in the history of Greek and Roman pharmacology and botany. It presents the actors in the transmission of pharmacological and botanical knowledge in antiquity and discusses how they established their authority through claims to expertise and effective treatments. It shows that much of that transmission occurred orally, and that attitudes toward the written word in general, and recipes in particular, were ambivalent. Next the article examines the question of efficacy from a cross-cultural and anthropological point of view. It notes that the notion of efficacy is culturally bound and asks whether it is possible to use ancient texts for bioprospecting, that is, to find “new” remedies. It calls for more collaborative studies involving historians, scientific archaeologists, and (ethno)-pharmacists.