Abstract: The acute toxicity and subchronic toxicity of an antifatigue functional food compound additive were studied in this experiment. The results showed that median lethal dose (LD50 )of the additive was higher than 15g/kg , so it was a kind of nonpoisonous substance according to the grading standards of acute toxicity of chemical substance. In 30-day-fed test , in which the additive content in feed was as high as 10% , the general condition of mice of experimental group was good during the fed period , the structure and function of their main organs and tissues were in normal condition. Therefore its maximum no effect level (MNL) was higher than 10g/kg and its subchronic toxicity was very low.