Chatbot is an emerging technology that helps in developing interactive systems. It is a software or computer program that simulates human conversation or "chatter" through text or voice interactions. Chatbots are used in different domains for different purposes. Chatbots allow humans to interact with the digital devices as if they were communicating with the real person. The paper aims at how chatbots could be used to help patients in the healthcare sector interact with the hospital with ease. The time taken to seek medical help should be reduced with the help of chatbots. Many chatbots offer services in the healthcare industry. The issue with these chatbots is that they can only respond to broad healthcare-related questions. The chatbot system for the healthcare industry is briefly discussed in this paper. Moreover, the paper discusses the different NLU(Natural Language Understanding), NLG(Natural Language Generation), and ML(Machine Learning) algorithms that should be used with the chatbot and evaluates them. This paper aims to introduce the role of chatbots in the healthcare sector and also understand the underlying architecture of chatbots. The paper explains the different types of chatbots and analyzes various chatbots used in health care systems. A SWOT analysis of the chatbot systems in the healthcare sector is evaluated. The paper also aims to identify the research gaps and future directions in contributing towards further study of chatbot technology in the healthcare sector. Various scholarly articles and websites are referred to and studied to gather information for this review paper. This review-based research article is a paper on chatbot technology to find the research objectives and the research gap in chatbot technology in the healthcare sector.