BACKGROUND: Chloroquine has been used to treat malaria for more than 70 years. Its safety profile and cost-effectiveness are well-documented. Scientists have found that chloroquine has in vitro activity against novel coronavirus (SARS-CoV-2). Currently, chloroquine has been adopted in the Protocol for Managing Coronavirus Disease 2019 (COVID-19) (Version 7) issued by the China National Health Commission for clinically managing COVID-19. OBJECTIVE: This review will focus on the antiviral mechanism, effectiveness and safety, dosage and DDIs of chloroquine, for the purpose of providing evidence-based support for rational use of chloroquine in the treatment of COVID-19. METHODS: Use the search terms "chloroquine" linked with "effectiveness", "safety", "mechanism", "drug-drug interaction (DDIs)" or other terms respectively to search relevant literature through PubMed. RESULTS: After searching, we found literature about antivirus mechanism, dosage, DDIs of chloroquine. However, studies on the effectiveness and safety of chloroquine treatment for COVID-19 for the general and geriatric patients are not enough. CONCLUSION: According to literature reports, chloroquine has been proven to have anti-SARS-CoV-2 effect in vitro and the potential mechanism of chloroquine in vivo. Pharmacokinetic characteristics and DDIs study are helpful in guiding rational drug use in general and geriatric patients. Although there have been reports of successful clinical application of chloroquine in the treatment COVID-19, more clinical test data are still needed to prove its effectiveness and safety.