Journal of Ethnopharmacology 122 (2009) 177–183 Contents lists available at ScienceDirect Journal of Ethnopharmacology journal homepage: www.elsevier.com/locate/jethpharm Review How scientific is the science in ethnopharmacology? Historical perspectives and epistemological problems Jürg Gertsch * Department of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang-Pauli-Str. 10, CH-8093 Zürich, Switzerland article info Article history: Received 24 November 2008 Received in revised form 4 January 2009 Accepted 4 January 2009 Available online 10 January 2009 Keywords: Ethnopharmacology Epistemology Methodology In vitro bioassays Concentration–effect Philosophy abstract This commentary is based on a general concern regarding the low level of self-criticism (-evaluation) in the interpretation of molecular pharmacological data published in ethnopharmacology-related journals. Reports on potentially new lead structures or pharmacological effects of medicinal plant extracts are mushrooming. At the same time, nonsense in bioassays is an increasing phenomenon in herbal medicine research. Only because a dataset is reproducible does not imply that it is meaningful. Currently, there are thousands of claims of pharmacological effects of medicinal plants and natural products. It is argued that claims to knowledge in ethnopharmacology, as in the exact sciences, should be rationally criticized if they have empirical content as it is the case with biochemical and pharmacological analyses. Here the major problem is the misemployment of the concentration–effect paradigm and the overinterpretation of data obtained in vitro. Given the almost exponential increase of scientific papers published it may be the moment to adapt to a falsificationist methodology. © 2009 Elsevier Ireland Ltd. All rights reserved. Contents 1. The past golden days of ethnopharmacology ....................................................................................................... 178 2. Are we facing a problem in contemporary ethnopharmacology? .................................................................................. 178 3. A philosophical problem ............................................................................................................................ 179 4. Misemployment of the concentration–effect paradigm – fact or artefact? ........................................................................ 180 5. Sociocultural consequences of artefact research in ethnopharmacology .......................................................................... 181 6. Popper’s critical rationalism is setting standards ................................................................................................... 181 Acknowledgments ................................................................................................................................... 182 References ........................................................................................................................................... 182 The great tragedy of Science – the slaying of a beautiful hypoth- esis by an ugly fact. Thomas Henry Huxley [1825–1895] Natural products are promising candidates for drug discov- ery and they still continue to play an important role in future small organic compound drug development programs (Newman and Cragg, 2007). While the typical industrial drug discovery pro- cess makes use of medium and high-throughput bioassay screening platforms to find promising compounds for a particular target, ethnopharmacology goes the opposite way; anecdotal efficacy of medicinal plants is put to test in the laboratory. The ethnopharma- cologist tries to understand the pharmacological basis of culturally * Tel.: +41 44 633 73 74. E-mail address: juerg.gertsch@pharma.ethz.ch. important plants. This approach is currently employed to study the pharmacopoeias of Traditional Chinese Medicine (TCM), the European pharmacopoeias, or the numerous medicinal plants from traditional ethnic groups. Thus, ethnopharmacologists typically use the working hypotheses derived from anthropological field- work, i.e. plant extract X is used in the cultural context Z to cure diseases A–D. Therefore, ethnopharmacology research is transdisci- plinary (Etkin and Elisabetsky, 2005), touching on areas like cultural anthropology, ethnobiology, and as the name implies, pharmacol- ogy. While cultural anthropologists have already pointed out the often insufficient quality of the ethnographic part in ethnophar- macology (Etkin, 1993; Soejarto, 2005), there is an increasing problem with the pharmacological part as will be discussed below. Reports on pharmacological effects of medicinal plants are growing almost exponentially. However, in the last 20 years few significant 0378-8741/$ – see front matter © 2009 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.jep.2009.01.010