Introduction. The use of medicinal plants, their geographical distribution, preparation methods, forms of administration, among others, are issues that require more research and at the moment there are no validated tools or instruments to retrieve this information. Objectives. To design and validate a questionnaire that identifies the use of medicinal plants. Design. Descriptive, bservational and transversal study. Location. Rural parishes surrounding the city of Babahoyo, located in the province of Los Rios, Ecuador. Participants. Heads of households in rural communities. Methods. A questionnaire called U-PlanMed was designed and then reviewed by a multidisciplinary team of experts in order to validate its logicality and content. The survey was also administered to 30 different heads of households on two occasions separated by 20-day intervals in the months of January and February 2015....