Abstract The late Edo and early Meiji periods were a time of significant transformation for Japan’s medical landscape, characterized by the blending of traditional practices and Western medical innovations. This paper examines the profound shifts in Japanese medicine during this era, and on introduction of Western style medical knowledge during Japan’s opening to the West in the 19th century reshaped existing paradigms of health and disease. Traditional Japanese medicine, including Kampo (herbal medicine) and acupuncture, coexisted with Western medical practices, particularly through the influence of Rangaku (Dutch studies), which began in the mid-Edo period. As Western medicine made its way from foreign missionaries and scholars, it initially gained traction among urban elites but gradually expanded across Japan, influencing both medical education and public health policies.The paper explores key historical figures, such as Ogata Koan, Hanaoka, Seishu, and Nagayo Sensai & etc, who played pivotal roles in developing medical theories into Japan's healthcare system. Through their efforts, Japanese medicine underwent transformation, with advancements in surgery, smallpox vaccination, and public health reforms. The Meiji Restoration of 1868 accelerated the integration of Western medical practices, leading to the establishment of modern medical institutions and the eventual creation of a national healthcare system.The medical revolution in Japan also set the foundation for the country’s contemporary healthcare system, which emphasizes universal healthcare, preventative care, and technological innovation. With the introduction of mandatory health insurance in 1961 and subsequent advancements in medical technology, including AI-powered diagnostics and robotic surgery, Japan’s medical system has become a global model. This paper provides a historical perspective on Japan's journey toward medical modernization, highlighting the intersection of cultural identity, innovation, and social change that shaped the healthcare system Japan enjoys today.