Development of an organism is accompanied by rapid and complex changes within a relatively short period, and embryotoxic chemicals administered to a mother during pregnancy can result in persistent lesions, general growth retardation, or delayed organ growth. In vitro toxicity tests are useful for evaluating the safety or hazards of small quantities of chemicals. Since cell death and inhibition of differentiation in mouse embryonic stem cells (ESCs) can occur within different concentration ranges of compounds, depending on the toxic potency of the compound, these cell properties can be used as guides for classifying the embryotoxicity of a compound. The use of multiple endpoints, such as assessing the inhibition of viability in ESCs (IC50ESC) and 3T3 cells (IC503T3), and reduction in embryoid body (EB) area (ID50EB), has the advantage of providing a detailed baseline for the classification of a compound’s toxicity level and for establishing a prediction model that utilizes those endpoints. The EB area-based toxicity test (EBT) is an animal-free, novel drug screening system that can be useful in evaluating of various embryotoxic chemicals within a short time.