The Internet of Things (IoT), is a concept that describes how objects that we are used in daily life will interact and negotiate with other objects over the internet. The amount of devices with Wi-Fi capabilities and built-in sensors keeps on increasing. IoT combines smart devices to provide smart services and applications like smart cities, smart healthcare, smart home, and digital farm etc. But it is very crucial to secure connected IoT devices and networks because of the nature of IoT system. In this paper, the existing works are analyzed and an IoT based healthcare system architecture is proposed. An authentication scheme to enhance the security of the proposed healthcare system is also present.