Although the ethnomedical system of the Highland Maya is generally well understood, little is known about the Tzeltal Maya ethnomedical syndrome Cha'lam tsots, or "second hair." In an attempt to better understand the emic conceptualization, and possible biomedical equivalence of Cha'lam tsots, ethnographic data from semi-structured interviews was collected from the Tzeltal Maya municipality of Tenejapa, in the central highlands of Chiapas, Mexico. Analysis of explanatory models elicited from 20 informants revealed a generalized agreement as to the etiology, symptomatology, course, prognosis, and treatments of this illness. Analysis of these findings will help guide further research into the etiology and biomedical correlate of Cha'lam tsots. This paper concludes with a discussion of the potential significance of this approach for an ethnoepidemiological study of ethnomedical systems, and for the improvement of basic health care services.