A special issue about Medical Ethnobiology is justified by many reasons; first,the contribution of ethnobiologists for a better understanding and description of the tradition al medical systems[see1] which constitute, for sure,for some peoples, a unique orat least complementary practice; second, the opportunity created for the dialogue with other important disciplines, such as medical anthropology, social medicine and medical Ethnobiology and others [1,2].And, also, we have a great variety of the oretical and methodological approaches that can be “addressed” as Medical Ethnobiology. This diversity is shown in the articles,which are part of this special issue.