John Flack, MD

Dr. John Flack is an internal medicine physician with over four decades of experience treating adult patients. He earned his medical degree from the University of Oklahoma College of Medicine in Oklahoma City and completed his internal medicine residency training at Oklahoma Memorial Hospital and Fairview-University Medical Center. Dr. Flack is board certified in internal medicine through the American Board of Internal Medicine and speaks English.

Dr. Flack practices at SIU Medicine clinics in Springfield, Illinois, including both the General Internal Medicine Clinic and the specialized Hypertension Clinic. He focuses particularly on treating high blood pressure in adults and children, including emergency situations involving dangerously elevated blood pressure. His diagnostic expertise includes performing aldosterone blood and urine tests to evaluate hormone levels that affect blood pressure regulation. Patients have given him an average rating of 4.4 out of 5 stars.