The emotions of anthropologists in the field can support the production of scientific questioning and methodological debates as they are processed in the moment or later, but how? This question is discussed based on ethnographic fragments related to care situations in West Africa. After recalling the role of social frameworks to establish the methodological legitimacy attributed to the sensitive and affective dimensions of field work by researchers, I will question their affects as both resources and risks. I will hint at how they can support knowledge by directing attention toward subjects to be questioned or by becoming part of the dialog within the investigation. Then I will highlight how they sometimes disturb it, dragging along in their wake individual and collective phenomena of memory and history. I will develop this point through the prism of interpreting the emotions of healthcare personnel practising medicine among the poor.