Chloroquine is primarily used as an antimalarial drug, effectively treating and preventing malaria caused by Plasmodium species. It works by interfering with the parasite's ability to digest hemoglobin, leading to its death. Beyond malaria, it has been explored for its immunomodulatory properties and used in the treatment of autoimmune diseases like rheumatoid arthritis and lupus erythematosus. During the COVID-19 pandemic, chloroquine and its derivative hydroxychloroquine were investigated for potential antiviral effects, though their efficacy remains controversial and not widely recommended. Additionally, it has shown promise in certain cancer therapies due to its ability to inhibit autophagy, enhancing the effectiveness of chemotherapy. However, its use must be carefully monitored due to potential side effects, including retinal toxicity and cardiac issues.