Abstract: LD₅₀ and the maximum administration dosage method were used in the experiment to observe and determine mice’s clinical symptoms, weight, organs indexes, liver and kidney functions in order to evaluate the safety of Agaricus blazei polysaccharide oral liquid. The results show that the LD₅₀ of Agaricus blazei polysaccharide oral liquid is higher than the actual non-toxic dosage（15 g/kg）. The maximum administration dosage is 67.2 g/kg and is equal to the 240 times of adult dosage. According to the indexes tested, the oral liquid has no adverse effects on mice’s liver and kidney functions. The oral liquid has low toxicity and is safe and reliable for the clinical application.

Key words: Agaricus blazei polysaccharide oral liquid, mouse, acute toxicity