Undernutrition occurs when there is poor intake or assimilation of energy and nutrients. If undernutrition is established within the first years of life, the health consequences are devastating. Early treatment of undernutrition is critical to reduce these consequences and milk plays an important role in this treatment. Cow’s milk is an excellent food due to the content and quality of its macro-and micronutrients. This has led to a steady increase in research and the use of milk in treating undernutrition since the beginning of the 20th century. In Chile, child undernutrition was practically eradicated between the decades of 1960 and 1980 due to the successful application of maternal and child public policies, within which the product Leche Purita was fundamental. However, the history of milk as part of nutritional policies in Chile began much earlier. Commemorating fifty years since the introduction of Leche Purita, we aim to summarize the historical importance of milk in Chile’s nutritional policies. We emphasize Leche Purita’s role in eradicating child undernutrition and reducing anemia among children.