Novel Coronavirus is defined to be the cause of COVID-19, recently. It’s known that COVID-19 causes excessive immune disruption of the body in severe cases. And also leaves long term effects on the body. Quercetin is reported to be effective on treatment and prophylaxis of other SARS like coronavirus infections. Quercetin is a very powerful antioxidant and scavenger flavonoid and it doesn’t have adverse events. In these findings, the investigators hypothesize that quercetin can be effective on both prophylaxis and treatment of COVID-19 cases. Therefore researchers of this study aim is to evaluate the possible role of quercetin on prophylaxis and treatment of COVID-19.