Zika virus is spread mainly by the bite of an infected mosquito, which can be passed from a pregnant woman to her fetus, thus leading to birth defects including more than microcephaly. It has been recently estimated that one-third of the world population will be infected by Zika in the near future, but unfortunately so far there is no vaccine or medicine for Zika. In particular, the special concern on the vaccine treatment to Zika and Dengue arising from antibody-dependent enhancement strongly emphasizes the key role of its NS2B-NS3 protease (NS2B-NS3pro) as a target for anti-Zika drug discovery/design due to its absolutely-essential role in viral replication. In response to the current global health emergency triggered by the Zika outbreak, we successfully obtained several active forms of Zika NS2B-NS3pro and further attempted to discover its inhibitors from eatable plants and traditional herbal medicines to immediately fight Zika. Here, for the first time, we discovered that quercetin, a flavonoid extensively existing in many fruits and vegetables, effectively inhibits Zika NS2B-NS3pro. We further quantify its inhibitory activity with IC50 of 26 uM; and Ki of 23 uM. As quercetin has been extensively found in fruits, vegetables, leaves and grains, our discovery would benefit the public to immediately fight Zika.