In my doctoral dissertation, I analyze homeopathy as a subaltern medical movement that both participated in and reacted to the cultural reforms and institutional regulations that characterized Mexico during the Porfiriato and the post-revolutionary periods. In a context where medical elites used science to consolidate their position amidst state institutions, homeopaths evolved into a group of professional physicians and lay practitioners who held an unorthodox view of medical science and whose institutions diverted the state's political and economic support. My analysis shows that professional societies, medical schools, and public health offices worked as an interconnected structure of regulatory centers. Here, homeopaths, regular medical practitioners, and state authorities used their understandings of science, education, and class to advance their positions in the professional arena, organize and administer medical institutions, and centralize political control. I argue that by using homeopathy as a scientific therapeutic method distinct from contemporary medical science and as a professional ideology that critiqued elitist medical training and practice, homeopaths aligned with the Mexican state's cultural and institutional reforms that aimed to provide scientific medical training to the working class. In this way, they resisted the marginalizing strategies implemented by medical elites' professional societies, professional education, and public health authorities. The professionalization of homeopathy, hence, reproduced in a smaller scale the tensions between lay and scientific knowledge, professional libertarianism and regulation, and the working and the privileged classes that characterized Mexico before and after the revolution of 1910. My dissertation thus investigates the influence of local social, cultural, and political realities in the construction of the boundaries between biomedicine and other healing traditions in modern Mexico. My work is based on extensive research in private and public archives of homeopathic medical schools, and government offices such as the Department of Public Health, the National University, the General Archives of the Nation, and the Historical Archives of Mexico City, as well as published homeopathic journals. This dissertation contributes to the history of medicine and public health in Mexico and in Latin America, the history of the medical profession, the history of alternative medicine, and the history of the Mexican revolution.