Tennis elbow, the common name for epicondylitis of the humerus, is treated with medication that can relieve the symptoms, but cannot be used to eradicate the disease, and non-steroidal anti-inflammatory drugs (NSAIDs) are often used. Epicondylitis of the humerus is an inflammation of the muscles and tendons connecting the extensor muscles of the forearm to the elbow joint, mostly due to long-term chronic injuries, and is common among tennis and badminton players. Clinical manifestations are pain on the lateral side of the elbow, numbness, and weakness in holding objects. Oral drugs commonly used for pain relief are non-steroidal anti-inflammatory drugs, such as naproxen, celecoxib, etc., and should be used according to the doctor’s prescription. Most of the patients can heal themselves after rest. The main purpose of treatment is to control the pain symptoms and relieve the condition. Arthroscopic surgery is feasible for those with intractable pain that is ineffective with conservative treatment. The disease is difficult to cure and can recur when the strain occurs again.