hcqs 200mg buy online, also known as hydroxychloroquine sulfate, is primarily used to treat autoimmune conditions such as rheumatoid arthritis and systemic lupus erythematosus. It works by reducing inflammation and suppressing the immune system's activity. HCQS is also prescribed for the prevention and treatment of malaria caused by certain parasites. It is often prescribed in combination with other medications to manage symptoms and improve quality of life for those with autoimmune diseases.