Blue milk, sometimes known as Bantha milk was a blue-colored liquid produced by a female bantha’s mammary glands. It could be found on most planets across the galaxy. The milk was well known for being very rich and refreshing, its opaque coloring suggesting that it was also sweet. The milk was also used to make a variety of yogurt, ice cream, and cheese.
The blue milk that Luke skywalker drinks as seen in Star Wars A New Hope.