Aims Arabidopsis thaliana l- and d-cysteine desulfhydrases (AtLCD and AtDCD) are two important H2S-generating enzymes. This study determined the effects of H2S derived from AtLCD and AtDCD on cadmium (Cd) toxicity in Escherichia coli. Methods and Results AtLCD and AtDCD were cloned into pET28a vectors and transformed into wild-type E.coli strain BL21(DE3), named BL21(LCD) and BL21(DCD). In the induced BL21(LCD) and BL21(DCD) compared with wild type, significantly higher H2S generation rates were observed. Additionally, higher survival rates, reduced contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2), decreased activities of superoxide dismutase and catalase under 220 mu moll-1 Cd stress were noted. We obtained similar results in the wild type treated with NaHS, a H2S donor. The above changes were substantially counteracted by the mixture of ammonia and pyruvic acid potassium (NH3+C3H3KO3), a synthetic inhibitor of H2S. Conclusions AtLCD and AtDCD catalyse the H2S production, generating an ameliorating effect against Cd-induced oxidative stress and resulting in E.coli resistance to Cd toxicity. Significance and Impact of the Study H2S as a gasotransmitter is certified to have an ameliorating effect against Cd toxicity, thus providing information for further research regarding the role of H2S in regulating resistance to the heavy metal stress in organisms.