Short communication FRED W. MARKHAM A METHOD FOR INTRODUCING THE CONCEPTS OF CHAOS THEORY TO MEDICAL STUDENTS ABSTRACT. Chaos theory is beginning to find applications in the field of medicine. The theory of chaos should be introduced to students to help them as they make the transition from learning the scientific literature to actually applying this newly acquired knowledge in clinical situations. Chaos theory will give the students a powerful conceptual framework from which they can better understand the limits of predictability in clinical situations. Failure to understand the limits of predictability in chaotic natural systems will invariably lead to frustration in both patients and physicians. KEY WORDS: chaos theory, medical education, how to teach the limits of predictability in medicine, chaos theory and cardiac disease As a practicing family physician at an academic institution, I have often watched as third and fourth year medical students struggle to rationally use the large amount of scientific information they have acquired during the first years of medical school. An example of this difficulty occurs when a student attempts to determine the best management for a patient with possible coronary artery disease. The students are taught that smoking, diabetes mellitus, and elevated cholesterol all increase the likelihood of coronary artery disease, but how does a student make use of the knowledge that the medical literature has shown that an individual patient with specific risk factors has a 50% chance of having significant coronary artery disease? Students want to know “Does the patient have coronary artery disease or not?” Terms like “high risk” and “low risk” are often used to give some guidance. These terms are often difficult to define precisely and are not particularly useful in deciding how to manage an individual patient. Is a 5% chance of death “high risk” or “low risk?” Firth has suggested that chaos theory can be employed to help students and doctors understand the limits of predictability. 1 I have found that introducing the concepts of chaos theory to third year students helps them to see how difficult precise prediction is in the clinical setting. I believe that acquainting students with such concepts as they make the transition from the classroom to clinical medicine gives them a conceptual framework Theoretical Medicine and Bioethics 19: 1–4, 1998. c 1998 Kluwer Academic Publishers. Printed in the Netherlands.