Radio Frequency Identification (RFID) is a modern communication technology, which provides authentication and identification through a nonphysical contact. Recently, the use of this technology is almost developed in healthcare environments. Although RFID technology can prepare sagacity in systems, privacy and security issues ought to be considered before. Recently, in 2015, Li et al. proposed SRTA, a hash-based RFID authentication protocol in medication verification for healthcare. In this paper, we study this protocol and show that SRTA protocol is vulnerable to traceability, impersonation and Dos attacks. So it does not provide the privacy and security of RFID end users. Therefore, we propose an improved secure and efficient RFID authentication protocol to enhance the performance of Li et al. method. Our analyze show that the existing weaknesses of SRTA protocol are eliminated in our proposed protocol.