Medicinal plant research may be pursued with several goals: the understanding of a native medical system, the elucidation of the rational basis for the medicinal use of a certain plant species, the development of low cost phytotherapcutics, the discovery of prototypic drugs, and so on. More often than not, the research project starts with the collection of indigenous medical knowledge in various parts of the world and generates a dissertation, a scientific paper or a drug. Usually, indigenous knowledge was crucial to the development of such products; nevertheless, indigenous groups tend not to benefit from the achievements of research. Ethnopharmacology involves a series of sociopolitical, economic and ethical dilemmas, at various levels. Most research projects involve more than one country (e.g., field work in a remote part of an underdeveloped country). Frequently host country scientists. visiting scientists, and informants disagree about these dilemmas. As a result, such research efforts are perceived as scientific imperialism: scientists are accused of stealing plant materials and appropriating traditional plant knowledge for financial profit and/or professional advancement. Many governments, as well as indigenous societies are increasingly reluctant to permit such research. Increasingly, funding for field work utilizing indigenous informants is coming from industry. Historically, neither native populations nor host countries have shared to a significant extent the financial benefits from any drug that reaches the market. Unless these issues are amply discussed and fairly resolved, medicinal plant research runs the risk of serving ethically questionable purposes.