In the past few years, the number of wireless connected devices has increased to a number that could reach billions in the next few years. While cloud computing is being seen as the solution to process this data, security challenges could not be addressed solely with this technology. Blockchain is the technology that underpins Bitcoin, it introduces manners to provide a fully autonomous secure system, by using smart contracts. Multi-layer BC is a very powerful solution to overcome many IoT challenges. This paper illustrates how Blockchain works, what are the IoT challenges, and how it can be integrated with Blockchain. We proposed in this work a multi-layer IoT/blockchain based architecture customized and designed to be used in the medical field. With this information interact many parties including the doctors, health service providers, insurance companies and pharmacies. The ultimate goal being to solve the problem of scalability and performance.