"Patient safety" is an important issue for patient self-care and for hospital management. How to decrease the opportunity of medication errors for patient is one of the important works in improving patient safety. The research proposes a system framework for building up an interoperability infrastructure for medication prescriptions exchange cross among different hospitals and clinics by XML technology. The framework of interoperability prescription that we propose is named "Taiwan Prescription Template (TPT)", which can be storage patient medical prescription by mobile device for patient self-care with medication, supporting physician diagnosis or patient medical referral. Patient can download their prescription after medical treatment by a portable device following TPT standard for improving patient safety by avoiding ADR event. We have deployed eleven major hospitals in Taiwan and are evidenced the benefit of deployment. TPT framework is a base infrastructure for building up more value adding patient self-care applications in the future.