Hydroxychloroquine sulfate tablets are an antimalarial drug and an immunosuppressant, which is a commonly used drug to improve the condition and antirheumatic drugs. The drug usually has a slow onset of action, with peak efficacy reaching about 3-4 months after administration. Hydroxychloroquine can be mainly used in rheumatoid arthritis, systemic lupus erythematosus, dry syndrome or other connective tissue diseases, mainly to relieve the symptoms of arthritis. It is also used as an adjunct in the treatment of skin rashes. In addition, hydroxychloroquine has photoprotective and cholesterol-lowering effects. Hydroxychloroquine has relatively few side effects and is currently considered the safest and most commonly used drug in the world for the treatment of rheumatic diseases, mainly because it does not affect the internal organ system.