What is the third leading cause of death in the United States?

• A. Heart disease
• B. Medical errors
• C. Cancer
• D. Stroke

Answer: (B)

Understanding how deaths are categorized helps explain why medical errors can appear among the top causes. Medical errors cover deaths that happen because of failures in the care process—things like misdiagnosis, incorrect or delayed treatment, medication mix-ups, errors during surgery, and hospital-acquired infections. These events are often preventable and reflect safety gaps in the health system rather than a disease running its natural course.

In some large analyses, when deaths are attributed to events tied to patient safety rather than to a specific disease, the tally can place that category in third place behind the leading disease-related killers. This framing emphasizes that improving the quality of care and patient safety can substantially reduce mortality, sometimes almost as much as addressing major diseases themselves. It’s a reminder that the health system’s performance matters for lives saved, not just the biology of illness.

Keep in mind that numbers and rankings vary by data source and how “medical error” is defined. Some studies rank different causes higher or lower depending on the methodology used.