Ancient recipes are usually short texts; one can easily find more than one recipe written on a single papyrus sheet or on the page of a Byzantine manuscript. Despite their brevity, however, they open an invaluable window onto a wide array of techniques and practices used to manipulate the natural world. Ancient recipes could pertain to various fields of science and technology—from cosmetics to cookery, from agriculture to horse care. In this post, particular attention will be devoted to two contiguous and, to a certain extent, overlapping areas of expertise: medicine and alchemy. As we will see, the works of two important authors, Oribasius and Zosimus of Panopolis, reveal the ways that recipe collections forged new forms of knowledge transfer in the fourth century CE.