Fisher and Welch review the growth in scope and complexity of health care delivery in the United States and argue that increased health care utilization risks producing overall harm. They begin by reviewing the growth of health care as a share of the economy, inflation-adjusted expenditures on health care, and the number of physicians per capita. The authors propose two levels of analysis for the growth of health care, “discrete” and “systematic”, and propose a framework for the mechanisms of harm. They propose several mechanisms by which harm can occur, review examples illustrating each, and offer partial prescriptions for minimizing the risk of harm as health care utilization expands.