We expect moral behaviour from scientists. Morality implies being a good person and being good at one's profession. The general view appears to be that the vast majority of scientists aim to achieve these high standards. Science prides itself on the 'self-correcting' mechanism in the scientific method, namely the requirement to reproduce findings before they are taken seriously. However, when findings are related to the adverse effects of chemicals there are several features that make this less effective than in some other fields of science. First, is the perception that everyone is exposed to chemicals and observations about chemical danger are immediately applicable to many people. Second, it is often easy to Summarize adverse findings in attention-getting headlines seen by the lay public before the slow process of replication and interpretation has time to work. Third, most regulatory toxicology Studies on a particular compound are only done once to minimise cost and the use of animals. Finally, the question posed about chemicals - are they safe? - is easy to ask but more difficult to test with appropriate studies. Fabrication of data in regulatory Studies was found to occur in several contract laboratories in the 1960s and this lead directly to the introduction of Good Laboratory Practice regulations. Now Studies submitted for regulatory purposes must comply with GLP regulations and this has virtually eliminated flawed studies due to fraudulent or careless behaviour. It is possible to discern different ways in which the expected standards have not been met. The first is in the intention of the work. Thus reports that the Roodeplaats Research Laboratory in South Africa was seeking to identify toxins that would kill without trace is an example where the intention is unacceptable. The second is in the conduct of the studies. Here the examples of William McBride and Michael Briggs who falsified data are pertinent. The example of the retraction of reports on the toxicity of ecstasy because the wrong compound had been administered indicates a degree of carelessness in the conduct of the study. The third is in the design and interpretation Of Studies. The report that genetic modification per se could render potatoes toxic has been criticised because of the inappropriate design and interpretation of the studies. Finally, that the reports of studies are biased because of conflicts of interest. Journals often require a declaration that the author has no financial conflict of interest. However, there are many other conflicts of interest with just as large an impact on the author's impartiality which are omitted from consideration. Gamesmanship has also entered the practice of toxicology, for example where strong assertions about conflict of interest are used to justify particular points of view. The main casualty from fraud, errors and gamesmanship is the perceived status of science itself. It is only gamesmanship that is on the increase. The remedies for these activities are explored. (C) 2004 Elsevier Ireland Ltd. All rights reserved.