The dissertation examines the significant yet neglected career of Yamei Kin, a Chinese woman whose transnational career influenced medicine and women’s rights in the United States and China. Although men dominated medicine, female doctors and nurses played an important role serving the poor and reaching women in China and Japan, where social norms restricted contact between the sexes. Thus, female medical professionals, represented by Yamei Kin, promoted the general welfare of the people, spread medical knowledge, and inspired more women to independence and excellence by their medical work. Yamei Kin is the first Chinese woman who obtained a medical degree in the United States (1885). A trailblazing physician, Kin broke the Chinese and Japanese prejudice against Western medicine and opened the medical profession to women in these two countries. She gave public lectures around America and England on women’s issues such as suffrage and prison reforms. She served as China correspondent of international women’s congress and shuttled among China, U.S. and Europe to improve women’s social status and promote the importance of women’s education. During World War I, she headed the research on soy food of the department of agriculture of the United States to study the potential of protein in soy and overcome a meat shortage during the war, enabling the public to maintain the same nutrition in their bodies even without meat.