A system for generating extensive data on diseases which is organized into a hierarchy or hierarchies of categories based on diseased organ systems, diseases or illnesses affecting or relating to the diseased organ systems and attributes of each disease or illness affecting or relating to the diseased organ systems. Key words, terms and/or sentences in each categories are used as a label, mark or tag for uniquely identify each category and are used for linking and connecting to related category, categories, topics and contents in other categories.