Abstract: OBJECTIVE To evaluate the acute toxicity of different processed kansui and its extraction on the model organism, zebrafish. METHODS Different processed kansui water extracts and alcohol extracts were prepared by reflux extraction method. The death of zebrafish was observed after exposure for 96 h to different processed kansui extracts with different concentration stages, which was the judgment for drug toxicity basis. The half lethal concentrations (LC₅₀) of different processed kansui extracts on zebrafish were calculated by SPSS Statistics 17. RESULTS Zebrafish in different processed kansui extracts all had acute toxicity reaction and showed apparent dose-toxicity relationship. Different processed kansui water extracts were significantly higher than alcohol extracts. Their order of toxicity from high to low was: the crude kansui, simple stir-baking kansui, kansui infiltrated with vinegar, and kansui stir-baked with vinegar. CONCLUSION With zebrafish as experimental animals, the crude kansui alcohol extract shows the highest toxicity, whereas kansui stir-baked with vinegar water exteact is lowest. The results provide evidence for the further understanding and evaluation on the toxicity of kansui and attenuated mechanism after vinegar processing.