Official X account of the American College of Physicians (ACP), the largest medical specialty organization and second-largest physician group in the U.S. The official Facebook Page of the American College of Physicians, the largest medical specialty organization in the United States with members in more than 145 countries worldwide. THE AMERICAN COLLEGE OF PHYSICIANS (ACP) IS A NATIONAL ORGANIZATION OF INTERNISTS - PHYSICIANS WHO SPECIALIZE IN THE PREVENTION, DETECTION, AND TREATMENT OF ILLNESSES IN ADULTS. ACP'S MISSION IS TO ENHANCE THE QUALITY AND EFFECTIVENESS OF HEALTH CARE BY FOSTERING EXCELLENCE AND PROFESSIONALISM IN THE PRACTICE OF MEDICINE.