The developments of Bioinformatics tools have made it possible to analyze and process interrelated diseases genes to design a common drug for the associated diseases. This book is organized based on five chapters, namely introduction, backgrounds, proposed methodology, results and discussion and conclusions. In this book, a common drug is designed for Bipolar Disorder, Schizophrenia, Coronary Heart Diseases and Stroke by analyzing and processing these diseases genes using R. This research creates a new dimension of using R in gene regulatory network which is the main potentiality of the research work.