N-Methyl-amino-2-nitro-4-N',N'-bis-(2-hydroxyethyl)-aminobenzene is a hair-dye ingredient. Its potential ability to induce gene mutations, in the yeast S. pombe and in cultured mammalian CH-V79 cells, mitotic gene conversion in the yeast S. cerevisiae, and unscheduled DNA synthesis in cultured human HeLa cells was evaluated. The chemical proved unable to induce detectable genotoxic effects according to these tests. The present data, together with others that show that the chemical is not mutagenic in Salmonella typhimurium or Drosophila, and is not clastogenic in mammalian cytogenetic assays (in vitro or in vivo), strongly support the non-genotoxicity of the chemical.