Dogs? extraordinary sense of smell is being harnessed in groundbreaking ways to detect human diseases, including cancer, Parkinson?s disease, and COVID-19. Recent studies demonstrate that trained detection dogs can identify unique volatile organic compound (VOC) signatures associated with illnesses, achieving sensitivities and specificities comparable to or sometimes exceeding standard diagnostic methods. This article explores the science behind canine olfaction, recent high-impact findings, real-world applications, and the potential and challenges of integrating detection dogs into modern healthcare.