Used primarily to prevent and treat malaria caused by mosquito bites. Also prescribed for autoimmune conditions such as rheumatoid arthritis and lupus, where it helps reduce inflammation, joint pain, and skin rashes. Works by modulating the immune response and interfering with the activity of certain cells involved in inflammation. Has been studied for other viral infections due to its ability to alter cell membrane pH, potentially inhibiting viral replication, though its effectiveness in such cases remains limited and controversial.