Objective To evaluate the developmental toxicity and genotoxicity of leonurine. Methods Leonurine was given orally to SD pregnant rats on the 6th to 15th day of pregnancy at the dose of 500, 1 000 and 2 000 mg/kg body weight. The control group received 0.5% CMC-Na solution orally. Pregnant rats were sacrificed on the 20th day of pregnancy to analyze the reproductive toxicity. Ames test, in vitro chromosomal aberration test of CHO cell and in vivo micronucleus assay were performed to investigate the genotoxicity of leonurine. Results There was no difference statistically in weight gain of pregnant mice between two groups at the dose of 500, 1 000 and 2 000 mg/kg of motherwort alkaloids. In vitro CHO cell chromosomal aberration test indicated that there was no statistical difference between leonurine groups (doses of 250, 500 and 1 000 μg/ml) and the solvent control group with and without metabolic activation system S9. The number of micronuclei in ICR mice did not increase (P>0.05) in the mouse bone marrow micronucleus test at the doses of 100, 500 and 2 000 mg/kg. Conclusion No significant maternal toxicity, embryo toxicity, fetal toxicity and teratogenic effects were observed with leonurine at 500, 1 000 and 2 000 mg/kg doses. Leonurine was not genotoxic in Salmonella typhimurium reverse mutation test, in vitro CHO cells chromosome aberration test or mouse bone marrow micronucleus test. It showed that leonurine had no developmental toxicity and genotoxicity under the conditions of the experiment.