INTRODUCTION: The e-health (electronic health) system is one of many cloud services which uses computer or electronic systems and cloud technology as its main source of operations for storing and sharing patient's medical data between healthcare service providers and patients. The health data records are kept in a semi-trusted third-party supplier (i.e., cloud). Therefore, its security has become the main concern as the data should not be accessible to unauthorized person. OBJECTIVES: To provide a brief knowledge on the security aspects of cloud-based e-health systems for further improvement in the field of e-health system security. METHODS: This paper presents a literature survey on secure cloud-based e-health systems including ninety-four research papers related to secure cloud-based e-health systems collected from different sources till 2019. RESULTS: The security mechanisms used to secure cloud-based e-health systems are divided into three categories (i.e., crypto, non-crypto, and biometric-based). Also some health related security laws, security mechanisms, advantages and limitations of security mechanisms for all categories are presented. CONCLUSION: This paper will be helpful to do further researches in the research area of e-health system as it consists of the analysis of security mechanisms, security laws, advantages and limitations of the security mechanisms.