This essay provides an explanation and interpretation of the undertreatment of pain by discussing some of the scientific, clinical, cultural, and philosophical aspects of this problem. One reason why pain continues to be a problem for medicine is that pain does not conform to the scientific approach to health and disease, a philosophy adopted by most health care professionals. Pain does not fit this philosophical perspective because (1) pain is subjective, not objective; (2) the causal basis of pain is often (...) poorly understood; (3) pain is often regarded as a mere symptom, not as a disease; (4) there often are no magic bullets for pain; (5) pain does not fit the expert knowledge model. In order for health care professionals to do a better job of treating pain, some changes need to occur in medical philosophy, education, and practice. (shrink)