Mobile medical applications are increasingly being used by patients and consumers. However, due to their complexity, these applications are normally only accessible to smartphone users. People using low-end cellphones cannot benefit from this new technology. The goal of this paper is to expand health service platform to lower-end cellphones, so that people in underdeveloped regions can benefit from it. In particular, we propose a scalable platform for lightweight health applications with novel and proactive client communication. Through the effective support of a multi-layered cloud platform, we assure the scalability, elasticity and reliability of the server side. With simple Short Messaging Service (SMS) channels, health workers and patients can access complex healthcare services with low-end cellphones. The multi-layered architecture provides separation of concerns and decoupling of communication and business logic. Furthermore, our proposed plug-in model can expand and customize functionalities. Extensive experimental results have demonstrated the effectiveness of the proposed platform.