New application of piceatannol

The invention relates to the field of medicines, in particular relates to new application of piceatannol. The invention provides application of the piceatannol in preparing medicines inhibiting bacteria and/or virus infection. The invention proves that the piceatannol has antibacterial effect on staphylococcus aureus, streptococcus pneumoniae and beta hemolytic streptococcus, and has an inhibiting effect on influenza a virus and RSV, the IC50 concentration of the piceatannol is 0.03 mg/mL, SI is 8.00. The in vivo experiment proves that the piceatannol has an obvious (less than 0.01) protective effect on the death of mice infected with the bacteria and the RSV, the effect is better than resveratrol. In addition, a result of a cytotoxicity test shows that the concentration of TC 50 of the piceatannol is 0.25 mg/mL, and the concentration of TC 0 is 0.06 mg/mL.