Regenerative medicine, particularly stem cell therapy, represents a revolutionary approach in treating previously incurable diseases. This review examines the current state of stem cell research, including embryonic, adult, and induced pluripotent stem cells, and their therapeutic applications in neurological, cardiovascular, and hepatic conditions. While clinical applications show promising results in tissue regeneration and organ repair, significant challenges remain, including cell purity maintenance, immunological rejection, and ethical considerations. Despite these obstacles, stem cell therapy continues to advance, offering hope for sustainable therapeutic solutions. This review highlights both the potential and limitations of stem cell applications in modern medicine, emphasizing the need for continued research and technological development for optimal clinical outcomes.