Mary Putnam Jacobi was a physician and researcher in the United States whose work advanced the understanding of women’s health in the late nineteenth century. She held senior positions at institutions such as the New York Infirmary for Women and Children and the Woman’s Medical College of the New York Infirmary, both located in New York City, New York. At a time when women faced substantial barriers in both healthcare and academia, Jacobi conducted scientific research that challenged widely held misconceptions about women’s physiology, particularly regarding menstruation. By performing laboratory experiments and advocating for vivisection, which is the practice of performing operations on live animals for research purposes, Jacobi played a role in advancing medical techniques that influenced future research. Jacobi’s work not only contributed to a more scientific understanding of women’s biology but also led to greater inclusion of women in medical research and practice.