Abstract: 【Objective】 The purpose of this experiment was to prepare probiotic fermented compound dandelion powder and evaluate its clinical safety. 【Method】 The probiotic properties of Saccharomyces cerevisiae and Bacillus subtilis were detected through artificial gastrointestinal fluid tolerance tests.The probiotic fermented compound dandelion powder was made by mixing Saccharomyces cerevisiae and Bacillus subtilis with 13 Chinese herbs，such as dandelion,Pulsatilla chinensis and hawthorn through solid-state fermentation.The quality of fermentation was evaluated by measuring the pH,odor,color and texture of the fermented products.The safety of fermented products was detected through acute toxicity test in mice.Thirty Kunming mice were randomly divided into 3 groups,with 10 mice in each group,half male and half female.Mice in test groups Ⅰ and Ⅱ were gavaged with compound dandelion powder preparation and probiotic fermented compound dandelion powder preparation at a dose of 5 000 mg/kg BW，respectively.Mice in control group were gavaged with an equal volume of normal saline，continuously for 7 days.Record the clinical symptoms and death situations of mice every day.After the experiment,the mice were weighed,blood was collected from the eyeballs,and the biochemical and immune indicators of the blood were detected.After post-mortem examination of mice,internal organs were collected,organ coefficients were calculated and tissue sections were made to observe pathological changes. 【Result】 The survival rates of Saccharomyces cerevisiae and Bacillus subtilis in artificial gastric fluid were 39.91% and 63.72%，and in artificial intestinal fluid were 47.61% and 22.04%,respectively.During the fermentation process of probiotic fermented compound dandelion powder,the pH showed a downward trend with the extension of time,reaching the lowest pH at 60 h.Sensory properties observation showed that the color of the fermented product had deepened,presenting a yellowish-brown color,soft texture,and emitting a rich sour aroma.No spoilage or deterioration had occurred.The results of the acute toxicity test in mice showed that none of the mice died during the test period.The clinical manifestations and histopathological examinations of the mice in experimental group showed no significant changes compared with those in control group.The liver index of mice in test group Ⅰ was significantly lower than that of control group (P＜0.05).The heart index of mice in test group Ⅱ was significantly lower than that of control group and test group Ⅰ (P＜0.05).The coefficients of other organs showed no significant differences among the groups (P＞0.05).The ALP activity in the serum of mice in test group Ⅰ was significantly higher than that in control group (P＜0.05),while there were no significant differences in other blood biochemical indicators and immune indicators among the groups (P＞0.05). 【Conclusion】 The probiotic fermented compound dandelion powder had good fermentation quality,was non-toxic to mice and had good safety.

Key words: probiotic; compound dandelion powder; mice; acute toxicity test