The aim of the eFilter project is setting up an IT system, which is based on health data filtered by the list of foods to which users want to consume. Our goal is a post-rehabilitation support system nutritionist PHR (Personal Health Record) data model preparation, which is suitable for desribing diseases, allergies and food sensitivities. First of all, we analyzed what kind of classifications and international standards exist referring to diseases. We have prepared a semantic data model, based on an EHR system (Electronic Health Record). These systems are designed to collect of all the information of a particular person connect with his health status. The design takes into account that all sensitive data in medical records data is essential for a reliable identification and authentication of patients and professionals. Electronic signature proved to be the most appropriate method. With the prepared xml schema we have reached our goal and we could make a formal description for defining several xml document classes. In addition to determine grammatical descriptions which xml structures can be defined by the rules you want to plot.