Ilya Mechnikov was a Russian biologist and immunologist, born on May 15, 1845. He is best known for his pioneering work in the field of immunology, particularly for his discovery of phagocytosis, the process by which certain cells engulf and digest harmful microorganisms. His research laid the foundation for understanding how the immune system protects the body from infections. In 1908, Mechnikov was awarded the Nobel Prize in Physiology or Medicine alongside Paul Ehrlich for their contributions to the study of immunity. He also studied the health benefits of probiotics and the role of gut bacteria in promoting longevity, influencing modern perspectives on nutrition and health.