Fog computing - a connection of billions of devices nearest to the network edge- was recently proposed to support latency-sensitive and real time applications. Electronic Medical Record (EMR) systems are latency-sensitive in nature therefore fog computing considered as appropriate choice for it. This paper proposes a fog environment for E-health system that contains highly confidential information of patients Electronic Health Records (EHR). The proposed E-health system has two main goals: (1) Manage and share EHRs between multiple fog nodes and the cloud,(2) Secure access into EHR on Fog computing without effecting the performance of fog nodes. This system will serve different users based on their attributes and thus providing Attribute Based Access Control ABAC into the EHR in fog to prevent unauthorized access. We focus on reducing the storing and processes in fog nodes to support low capabilities of storage and computing of fog nodes and improve its performance. There are three major contributions in this paper first; a simulator of an E-health system is implemented using both iFogSim and our iFogSimEhealthSystem simulator. Second, the ABAC was applied at the fog to secure the access to patients EHR. Third, the performance of the proposed securing access in E-health system in fog computing was evaluated. The results showed that the performance of fog computing in the secure E-health system is higher than the performance of cloud computing
