|Clinical Decision Support System (CDSS) plays imperative role in emulating decision making, providing evidence based decisions and solving complex medical problems from over 50 years. It has enormous impacts on quality of care, patient safety and avoidance of medical errors. CDSS are generally categorized into four major types, phases or stages namely standalone, integrated, standard-based and services oriented. In this article, the state of the art of CDSS systems is studied, and Smart CDSS that has been developed by the authors is presented as an example clinical scenario. This work describes, targeted scope of smart CDSS and working process including knowledge acquisition, knowledge execution, and integration with existing clinical workflows. Smart CDSS is incorporated with two complex and important domain including dementia and head and neck cancer workflows for testing and evaluations which achieve an impact on both improving patient care and reducing medical cost. We conclude that the smart CDSS can be integrated into any existing clinical workflow and have the capability to be extended to any desired disease.