Duplicate medication between enterprises not only wastes medical resources, but also endangers a patient's safety. However, medication information may come from different medical institutes and use different terminologies. The majority of patients do not know the names of these drugs; and for other doctors, they may also not understand medication information content. In order to avoid duplicate medication, drug allergy or other drug incidents, this study hope to implement web services for sharing medication information between enterprises base on IHE Cross-Enterprise Document Sharing (XDS) and RxNorm, making the medication information correspond to standardization. Through the consistency of these standards, the doctor could refer to a complete medication record of the patient in the past when prescribing in order to avoid the duplication of a drug. Because patients in recent years care more about their own health management consciousness, this service also provides automatic duplicate medication check.