A computer implemented and interactive system for obtaining a patient's symptoms and other indications of disease, which are utilized to determine the probable existence of disease. The program generates a series of inquiries which are displayed to a patient who is asked to identify the body part which the patient believes is causing a physical or mental problem. The system's program uses a database of diseases and related symptoms to generate questions. Based upon the patient's answer to each question, the program determines the probability that the patient has one of the diseases contained in the database. When the patient has completed answering all of the questions, the system's program generates a report of the probable existence diseases, including the patient's most probable disease.