Regular full-length papers should be subdivided into the following sequence of sections: Title page, Abstract, Introduction, Materials and methods, Results, Discussion, Acknowledgements, References, Legends to figures, Tables. The Title page must include the telephone and fax numbers and E-mail address of the corresponding author. In the Journal, the Materials and methods, Acknowledgements and References sections are printed in smaller type to accommodate more text. The Materials and methods section must give precise details of strains, concentrations and solvents. Where an activation system has been included it is necessary to know (i) the source, (ii) the inducer and (iii) the concentration treatment time, and incubation time with conditions should be given. Positive and negative controls together with their concentrations must be included. The number of replicates and the number of repeat experiments should be stated. Additional factors for in vivotests should include age, weight, sex and total number of animals used in each experiment. A detailed dose regime is required. Papers for the Mutagenicity testing section should conform to the above requirements. In addition, results should be presented in tabular form.