Ethnomedicinal research has historically focusses on botanical products, ignoring, by and at large, the records on animal-based medicine. Whenever non-botanical -e.g. animal-based- remedies appear on indigenous pharmacopoeias, these are taken with little interest and are explained as de facto - i.e. They occur because they occur- This lack of interest impedes ethnobiologists to develop further investigations or theoretical afterthoughts that would enable to articulate ethnomedicinal systems as holistic ecological adaptations. Among non-botanical medicines, those from marine origins hardly receive any mention. This dissertation describes how do botanical and marine medicines relate within an ethnomedicinal knowledge system. In this research, I focussed on Seri ethnomedicine. The Seri are an indigenous group of hunter-gatherers located in the mainland portion of the Central Gulf Region in Sonora, Mexico. Seri posses a pragmatic ethnomedicinal system which provides a rich case for this examination as there is little room for cultural features to restrict the flow of ethnomedicinal knowledge between informants. During a one year long survey in a Seri village, I used participant observation, focus-group interviews, and an ethnomedicinal knowledge test to interview 67 Seri informants. By presenting the individuals with an ethnomedicinal knowledge test, I evaluated each informants proficiency in ethnomedicinal knowledge and gathered information on the organoleptic strategies used in the selection of medicinal organisms. I then determined the toxicological profiles of marine and terrestrial medicines. Seri marine and terrestrial medicines are part of one single pharmacopoeia. The organisms are selected under the same criteria; toxicity. Organisms with higher toxicity profiles are used against more ailments. Flavor plays an important role in detecting toxicity. Organisms with bitter or acrid flavors are characteristically associated with high toxicity. Seri ethnomedicinal knowledge transmission is conditioned to gender roles. Fathers teach about marine medicine while mothers teach about botanical medicine. Women know more about botanical medicine than men. However, 18% of marine medicine has a gynecological application, and women know at least as much marine medicine as men. By comparing the selection criteria of marine versus terrestrial medicine an important generalization can be formulated; the brain senses medicines in bitterness