This article offers both a contribution to the ethnography of ethnomedicine among the Kulina Indians of western Amazonia--a region in which there has been little ethnomedical research--and an extended illustration of the value of the concept of "personhood" in the analysis of ethnomedical beliefs and practices. I argue that the current medical anthropological fixation on the Body is neither good ethnography nor productive theory, and I use the Kulina example to illustrate how the cultural dimensions of personhood provide a more satisfactory framework for the understanding of illness. Kulina conceptions of illness are closely linked to the substances and processes through which personhood is acquired, expressed, and transformed. I consider the two major categories of illness in Kulina ethnomedicine, and focus special attention on the more serious of these: potentially fatal illnesses that are linked to witchcraft and to the violations of prohibitions. I suggest how these illnesses serve as languages for the simultaneous negotiation of social issues and personhood.