Local empirical knowledge about medicinal properties of plants is the basis for their use as home remedies. Particularly in developing countries such remedies still are an indispensable resource for everyday health care. They form the basis for numerous studies on drugs from natural sources. Like other indigenous groups across the world, the Ch'orti' Maya in Eastern Guatemala are currently experiencing a phase of dramatic cultural change, with their traditional knowledge about plants being in great danger of disappearing. During 17 months of fieldwork, medicinal plant uses were documented using a semi-quantitative approach and analysed using ethnopharmacological methods. The most important groups of illnesses treated with plants were gastrointestinal complaints and illnesses associated with pain and fever. Field data were compared with mostly unpublished historical data collected in the 1930s by the anthropologist Charles Wisdom. This comparison showed that medicinal plant uses that are more consistent over time are also shared by a larger number of people. A literature search on the most frequently mentioned medicinal plants showed that, even for widely used medicinal species, phytochemical and pharmacological data are insufficient for fully understanding their therapeutic profile. Whereas a few examples of potentially dangerous practices were encountered, the limited amount of information available mostly supports local medicinal plant usage.