The MDX diagnostic decision support system contains a multitude of clinical facts as reported in a variety of medical textbooks and national medical journals. The database was custom designed for the medical diagnostic process and offers users the widest range of diagnostic knowledge available from a single source in the industry. The database consists of diseases, conditions, chemicals, drugs, and toxins that are known to cause medical illness. Each causal element has an associated file for signs, symptoms and findings. This fully referenced source of encoded clinical knowledge used in MDX comes from the world's experts as they transmit their experience in the written word of books and journals.