50 Australian Aboriginal Studies 2002/1 M.J. Rowland Environmental Protection Agency Abstract: The practice of geophagy, in particular the consumption of clay and charcoal by humans, is global in its distribution, is of considerable antiquity and has a number of complex functions. One of these functions is the ability of clays and charcoals to adsorb toxins. This has been known anecdotally for some time and has more recently been scientifically demonstrated. This article reviews evidence that indicates that the adsorptive qualities of clays were well recognised by Indigenous Australians. This Indigenous knowledge therefore has significant impli- cations for the timing and nature of adaptation to many of the toxic plants of Australia. It is proposed that knowledge of these adsorptive qualities arrived with the earliest colonisers and enabled them to adapt to toxic plants earlier and more easily than has usually been assumed. Introduction The consumption of clay and charcoal—known as ‘geophagy’—is generally adaptive, has a global distribution, is of considerable antiquity and has a number of complex functions. One of these functions is the ability of clays and charcoal to adsorb toxins. Geophagous behaviour is common among a range of animals, and humans could easily have imitated and adapted it to their own needs by observing these animals. It therefore follows that the practice of geophagy could have arrived on Australia’s shores with the initial arrivals, at least 40,000 years ago. It is proposed that the ability of clays and charcoal to adsorb toxins may have enabled people to rapidly adapt to some of the many toxic plants of Australia. Such a view brings into question, for example, Beaton’s (1977:201–3) observation that ‘there is no such thing as people who eat cycads, and those who are are only just learning about how to prepare them’. It also raises doubts about his proposed mid to late Holocene introduction of a ‘Basic Leaching Technology’. Questions are also raised concerning Webb’s (1973) classic interpretation of the need for Indigenous Australians to ‘eat, die, and learn’ in adapting to the flora of Australia. Other significant issues, relating to Aboriginal use of clay and charcoal requiring further research, are also highlighted. Geophagy—a definition The eating of clay or charcoal and a range of other substances might superficially be considered bizarre or at best to be of limited adaptive value, and this is reflected in a long and continuing debate about the benefits or otherwise of geophagy. Avicenna, for example, who lived around AD 1000, saw it as a negative practice and called for the control of it ‘in boys by use of the whip, in older patients by restraints, prison and medical exhibits, while incorri- gible ones are abandoned to the grave’ (Halsted Geophagy: an assessment of implications for the development of Australian Indigenous plant processing technologies