The side effects of thymidine injection are mainly nausea, fever, dizziness, chest tightness, weakness, etc. A few patients may also experience drowsiness. Thymidine can improve the immunity of human body, because thymidine contains a part of hormone, which can induce the differentiation and maturation of human immune cells and enhance the production of immune cells. For the human body, especially for the weak or elderly people, long-term application will play a positive role in preventing diseases. As an immunomodulator, thymidine is not recommended for long-term application and should be applied under the guidance of a doctor to avoid excessive immune response that may lead to related diseases. Thymidine is widely used among patients with tumors, and it can also be used for all types of heavy hepatitis, chronic active hepatitis, cirrhosis, and herpes zoster, genital herpes, acromegaly, etc. It can also be used for various immune diseases.