Millions of people are suffering from fatal diseases such as cancer, AIDS, and many other bacterial and viral illnesses. The key issue is now how to design lifesaving and cost-effective drugs so that the diseases can be cured and prevented. It would also enable the provision of medicines in developing countries, where approximately 80% of the world population lives. Drug design is a discipline of extreme importance in chemoinformatics. Structure-activity relationship (SAR) and quantitative SAR (QSAR) are key drug discovery tasks.