Today, the healthcare sector is suffering from multiple security vulnerabilities that make it vulnerable to various types of cyberattacks. Therefore, robust security solutions need to be implemented in order to resolve these vulnerabilities. In this context, blockchain technology has emerged as a promising solution in several sectors, including the healthcare sector. It ensures enhanced security and greater transparency. It also boosts patient confidence and optimizes operational efficiency. In this paper, we first present an overview of the main classic healthcare applications: medical records management, traceability of medicines, and research and clinical trials. We then present a detailed analysis of the critical security vulnerabilities threatening these applications. Afterwards, we explain how blockchain technology can help to address these vulnerabilities. Finally, we discuss the various possible methods that aim to prevent traditional blockchain-related attacks in these healthcare applications and how blockchain technology is impacting and transforming the healthcare sector.