Chloroquine is an antimalarial drug and autophagy/lysosome inhibitor. Chloroquine also suppresses Toll-like receptor-9 (TLR9) protein expression. Chloroquine is highly effective agianst SARS-CoV-2 (COVID-19) infection with EC50 of 1.13 μM in Vero E6 cells. Chloroquine has anti-HIV-1 activity.