An in vitro toxicity assay based on human blastocyst-derived stem cells for the detection of toxicity in the human species is provided, which enables novel detection of in vitro human toxicity for a substance and/or more efficiently detects human toxicity compared to non-human assays. Furthermore, the detection of toxicity for substances is enabled, which is known to display inter-species differences and the toxic effect was not detectable by toxicological tests in mice.