BackgroundUp to one half of the population in Africa, Asia and Latin America has little access to high-quality biomedical services and relies on traditional health systems. Medical pluralism is thus in many developing countries the rule rather than the exception, which is why the World Health Organization is calling for intercultural partnerships to improve health care in these regions. They are, however, challenging due to disparate knowledge systems and lack of trust that hamper understanding and collaboration. We developed a collaborative, patient-centered boundary mechanism to overcome these challenges and to foster intercultural partnerships in health care. To assess its impact on the quality of intercultural patient care in a medically pluralistic developing country, we conducted and evaluated a case study.MethodsThe case study took place in Guatemala, since previous efforts to initiate intercultural medical partnerships in this country were hampered by intense historical and societal conflicts. It was designed by a team from ETH Zurich’s Transdisciplinarity Lab, the National Cancer Institute of Guatemala, two traditional Councils of Elders and 25 Mayan healers from the Kaqchikel and Q’eqchi’ linguistic groups. It was implemented from January 2014 to July 2015. Scientists and traditional political authorities collaborated to facilitate workshops, comparative diagnoses and patient referrals, which were conducted jointly by biomedical and traditional practitioners. The traditional medical practices were thoroughly documented, as were the health-seeking pathways of patients, and the overall impact was evaluated.ResultsThe boundary mechanism was successful in discerning barriers of access for indigenous patients in the biomedical health system, and in building trust between doctors and healers. Learning outcomes included a reduction of stereotypical attitudes towards traditional healers, improved biomedical procedures due to enhanced self-reflection of doctors, and improved traditional health care due to refined diagnoses and adapted treatment strategies. In individual cases, the beneficial effects of traditional treatments were remarkable, and the doctors continued to collaborate with healers after the study was completed. Comparison of the two linguistic groups illustrated that the outcomes are highly context-dependent.ConclusionsIf well adapted to local context, patient-centered boundary mechanisms can enable intercultural partnerships by creating access, building trust and fostering mutual learning, even in circumstances as complex as those in Guatemala. Creating multilateral patient-centered boundary mechanisms is thus a promising approach to improve health care in medically pluralistic developing countries.