Based on the examination of some passages of Galen’s Anatomicae administrationes preserved only in Arabic translation, this paper explores to what extent Galen could be concerned with animal suffering. It appears that the Greek physician and famous anatomist makes a clear distinction not only between dissection and vivisection, but also between the dissection of monkeys and that of other animals. This paper explores in particular how the use of the relatively rare adjective εἰδεχθές (obnoxious appearance) can shed new light on the ambivalent relationship between physicians and animals.