Healthcare system can be enhanced vastly with the use of modern information technology. Still now in underdeveloped and developing countries, traditional paper based system is being used in healthcare. Although very few organizations use computer based system, they could not establish a ubiquitous network among patients, physicians and government. Cloud computing is the emerging technology which can be used to develop a heterogeneous network to improve the system. In this article, a three tier cloud based application “eHealth Cloud” has been developed which will involve different parties to improve old-fashioned healthcare system. RIA (Rich Internet Application) based client, SimpleDB based server and a logic layer have been designed to build an easily accessible network. By using the “eHealth Cloud”, enormous electronic medical record (EMR) will be stored everyday. This huge size of data can lead us with new research opportunities. Data mining from the large amount of EMR has been proposed. The process of data mining, a standard for exchanging data and a mining model is described. Finally, the challenges and future research options are directed.