The Preventive Medicine Research Institute (PMRI), founded by Dr. Dean Ornish, is a non-profit organization dedicated to pioneering research in lifestyle medicine. Based in Sausalito, California, PMRI focuses on scientifically demonstrating how comprehensive lifestyle changes can prevent, manage, and even reverse chronic diseases such as heart disease, type 2 diabetes, and early-stage prostate cancer.

PMRI's approach emphasizes the synergy of four key elements: plant-based nutrition, moderate exercise, stress management techniques (like yoga and meditation), and fostering meaningful social connections. These interventions are designed to address the root causes of chronic illnesses rather than just their symptoms.

PMRI has conducted groundbreaking clinical studies that have reshaped the understanding of health and disease. Their findings have been published in leading medical journals and have influenced national healthcare policies, including Medicare coverage for lifestyle intervention programs.