This chapter introduces blockchain as a transformative technology in healthcare, addressing key challenges like data security, interoperability, and trust. The chapter traces the evolution of blockchain technology through three generations, from digital currencies to smart contracts and scalability solutions. Various blockchain platforms, such as Ethereum, Hyperledger Fabric, and Corda, are evaluated based on their suitability for healthcare use cases, including EHR management, clinical trials, and drug supply chain integrity. The chapter concludes with best practices for secure, scalable, and compliant blockchain implementations.