In the late 19th-century United States and Europe, infants died at high rates from diarrhea. Physicians and social justice advocates responded to the public health crisis with attempts to clean up the water and cows’ milk supplies, as well as social welfare legislation and assorted educational efforts to help mothers better care for their children. Most visible among the educational efforts were breastfeeding campaigns. A century later in developing countries, physicians and activists were confronted with a similar problem—infants dying from diarrhea due to the unethical advertising and marketing practices of formula companies. I argue in this article that crusades for social justice at the most basic level—to ensure that children will live to adulthood—have long been connected with efforts to safeguard mothers’ ability to adequately breastfeed their children.