Abstract: Method for testing of the embryotoxicity in the chicken embryo consists in reading the response of caudal morphogenetic system (CMS) of a chicken embryo to the presence of the tested substance in subgerminal fluid. The function of the caudal morphogenetic system is evaluated 24 hours after application by a simple quantitative parameter -- the length of a newly-formed part of the trunk. The substance, which interferes with some of the basic morphogenetic processes, slows down, stops or modifies the formation of the shape of the caudal part of trunk. Considering that the quantitative parameter is used as the index of the CMS function, each member of the experimental set presents information, not only the dead and malformed embryos as in classical methods. The second part of the test, i.e.