Many of us are familiar with milk as a food in our supermarket aisles, whether as a beverage that pairs well with cookies, or as the starting ingredient for cheese and yogurt. But milk is also part of what makes us mammals, a class of animals that produces milk as the first food for our young. Our lecture will begin with a discussion of the "recipe" for milk and investigate why the recipe may vary among species. We will also take a closer look at how different parts of milk support the growing infant. Next, we will dive deeper into how milk supports an infant's immune system. Finally, we will conclude by discussing current and future applications of milk as medicine.