The American College of Physicians (ACP) is a professional organization of internal medicine physicians in the United States. It is the largest medical-specialty organization and second-largest physician group in the country. ACP provides education, advocacy, and resources for its members to enhance patient care and promote the practice of internal medicine. The organization also publishes the Annals of Internal Medicine, one of the most widely cited medical journals in the world. ACP is dedicated to advancing the field of internal medicine and improving healthcare for all patients.