Aspirin is a first-line treatment for the fever and joint-pain symptoms of acute rheumatic fever . The therapy often lasts for one to two weeks, and is rarely indicated for longer periods. After fever and pain have subsided, the aspirin is no longer necessary, since it does not decrease the incidence of heart complications and residual rheumatic heart disease.   Naproxen has been shown to be as effective as aspirin and less toxic, but due to the limited clinical experience, naproxen is recommended only as a second-line treatment.  
Aspirin is a nonsteroidal anti-inflammatory drug (NSAID) that is commonly used to relieve pain. But, aspirin also may prevent the formation of blood clots. Aspirin does this by inhibiting platelets from promoting clotting in blood vessels where cholesterol and plaque may be partially blocking blood flow. This clotting can lead to heart attack and stroke. By inhibiting clotting, aspirin helps reduce damage to the heart and brain and helps prevent heart attack and stroke.