Chloroquine is a medication primarily used to prevent and treat malaria, a disease caused by parasites transmitted through mosquito bites. It works by interfering with the growth of the parasites in the red blood cells of the host. In addition to malaria, chloroquine has also been studied for its potential use in treating autoimmune diseases like rheumatoid arthritis and lupus. Despite its effectiveness, chloroquine can have side effects, including nausea and headaches. It is important for patients to follow their doctor's instructions when using this medication. In recent years, chloroquine gained attention during the COVID-19 pandemic, but its effectiveness against the virus remains debated.