This paper presents a cloud-based system for health care applications. Our system has advanced features for preserving privacy which are essential for health care applications that deal with confidential data. We describe some of the bioinformatics applications which our system is designed for. Performance is significantly enhanced by caching, and enhanced clients for performing part of the computations are a key component of our system. Cloud, due to its pay-as-you-go pricing and API based deployment model, has become widely used for delivering and maintaining infrastructure technology for businesses. However, there are significant challenges with using the cloud for applications with strict privacy and compliance requirements; health care applications fall in this domain. This paper describes an architecture and solutions for handling these types of applications.