This article addresses important epistemological issues raised by Barry Hallen and J. Olubi Sodipo’s pioneering philosophical fieldwork among Yoruba herbalists or masters of medicine (onisegun). More precisely, I shall primarily investigate, as well as object to, the unduly restrictive view they take on testimony in Yoruba epistemic practice. With this criticism as the starting point, but still based on the cases Hallen and Sodipo provide, I explore different ways in which an “oral culture” like Yoruba (as traditionally depicted) can rely (...) on testimony as a source of justification without succumbing to the gullible and uncritical attitude towards tradition such societies have been charged with. To this purpose, I put to use relevant developments in analytic epistemology taking place after Hallen and Sodipo published their work. (shrink)