Septic arthritis is a septic infection caused by bacteria from lesions elsewhere in the body spreading to the joint cavity through the bloodstream or by bacteria entering the joint through a wound due to an open injury. It is common in children, and the most common sites are the hip and knee joints. The systemic symptoms are caused by the deficiency of positive energy and residual toxicity, which may include high fever, chills, general malaise, loss of appetite, and thick yellow tongue coating. Local symptoms are mainly redness, swelling and pain in the affected joints. If there is too much fluid in the joints, it may lead to muscle spasm around the joints, which may lead to joint dislocation or subluxation. Septic arthritis is a very serious disease, and if left untreated, the prognosis is very poor. Therefore, if the above symptoms occur, please seek medical attention promptly to clarify the diagnosis and provide active treatment.