Taiwan's advanced health care system is one of the world's best health care services. Elderly citizen and chronically ill patients benefitted from this system the most. However, under this system, patients can only get brief description about drugs and directions of their usage printed on the medicine bag. With rapidly development of mobile devices, helping patients to obtain critical medication information with mobile technology is an important issue. Currently, medical-related Apps on the App marketplace only allow user to query general drug information. Furthermore, for patients have two or more drugs, they need to inquiry drug information one by one, which is quite troublesome for the elderly patients. Therefore, the objective of this study is to solve the above problems by developing a “Health Care Assistant” App. It can provide personal medication care, food care, as well as drug information for the patients. This App has nine functions with amazing images and vibrant colors including: making an appointment, recommended pharmacies, health news, personal settings, diet lights, medical records, scanning prescriptions, transfer prescriptions, drug information. The distinguishing feature of this App is integrating with the national health insurance (NHI) declare system and health care system of Taiwan, so users can get the latest personal medical information without complicated process.