The European Community (EC) has been developing a plant bioassay within the Organization for Economic Cooperation and Development (OECD), Terrestrial Plants, Growth Test guidelines. The aim has been to obtain a relatively simple, reproducible test that is both flexible and economically viable. Over the past ten years, European government and contract laboratories, including the ICI Brixham Laboratory, have examined the suitability of a range of test species and pot sizes for use in plant tests. Other parameters assessed include the use of pregerminated seeds and the value of randomized experimental design. During this period, these establishments have taken part in two Ring Tests (interlaboratory comparative trials), and this has resulted in several refinements to the test. ICI Brixham Laboratory has adopted the basic guideline of this plant test and has used it, with slight modification, to assess the effect of a range of organic and inorganic chemicals on emergence and early plant growth of a number of plant species. The method is also suitable for adaption to assess the effect of volatile chemicals and of soils amended with sludges from treatment processes on plant growth.