Fluid buildup in the knee requires targeted treatment for the different causes of synovitis. Degenerative synovitis can be caused by oral non-steroidal anti-inflammatory drugs, rheumatoid causes require oral anti-rheumatic drugs, while infections that cause effusions require oral antibiotics. Traumatic synovitis requires drugs such as Yunnan Baiyao. 1. Degenerative knee synovitis: long-term chronic knee injury or knee cartilage degeneration, will stimulate the synovial membrane to appear aseptic inflammatory reaction, appearing knee pain, swelling and impaired mobility manifestations, the acute phase of the knee can be seen in the increase of fluid affecting the joint activities. Oral non-steroidal anti-inflammatory drugs such as celecoxib and acetaminophen can improve the sterile inflammatory reaction. 2. Rheumatoid arthritis: The main symptoms of rheumatoid arthritis are pain, swelling and joint deformity, and the swelling of the knee joint is mainly caused by synovial and articular cartilage lesions. Oral anti-rheumatic drugs can relieve knee effusion, such as Leflunomide and Hydroxychloroquine. 3. Infection: Septic knee infection can also cause knee effusion, which is mainly caused by bacterial proliferation leading to the continuous increase of purulent fluid. For bacterial infection of septic knee arthritis can be treated with oral antibiotics such as penicillin or vancomycin. 4. Traumatic synovitis: trauma or sports can also occur synovial membrane injury caused by synovitis, knee effusion. It is mainly bleeding and requires braking and external immobilization. Oral Yunnan Baiyao and non-steroidal anti-inflammatory drugs such as Loxoprofen sodium are also needed. Knee effusion is recommended to the hospital to clarify the condition, oral medication needs to be in the doctor to clarify the cause of the disease after the guidance of medication.