Ethnomedicine has historically served as a foundational source for drug discovery and therapeutic innovation. Traditional knowledge systems across civilizations-preserved through oral traditions and ancient manuscripts-have contributed significantly to the identification of bioactive compounds and the development of modern pharmacology. This paper traces the evolution of medicine from indigenous practices to organized systems and ultimately to modern scientific medicine. It highlights representative ethnomedicinal examples that led to validated therapeutics, discusses historical literature documenting medicinal knowledge, and evaluates contemporary challenges in drug discovery from plant sources. Emphasis is placed on quality control, regulatory frameworks, safety considerations, systems biology, and novel drug delivery approaches. Ethnomedicine remains a vital reservoir of pharmacologically active compounds and demands systematic scientific integration for future drug development.