To assess the effect of GA on infectious viruses, we performed GA dose-response experiments. The cells were treated with different GA concentrations ranging between 1 µM and 20 µM. We demonstrated a dose dependent effect of GA on HCMV, HSV-1, and ZIKV. The effect of GA was tested in several cell types including HEp-2 (human epithelial carcinoma), 293T (human embryonic kidney), HFF and NHA (normal human astrocytes). GA was shown to have a viral inhibitory effect in all of the tested cells with no cytotoxicity within the active inhibitory range.