Coffee and milk can be drunk together, and there is no effect on health when they are drunk together. Coffee is bitter, made from ground coffee beans, contains a large amount of caffeine and trace elements, etc., can stimulate the brain nerve excitability increase, play a refreshing, brain-boosting, improve the spirit of the role. Milk is sweet and contains a lot of protein, carbohydrates, calcium, iron, phosphorus and other nutrients. Every 100 ml of whole milk contains 54 calories, of which 3 grams of protein, 3.2 grams of fat, 3.4 grams of carbohydrates and 104 milligrams of calcium. There is no conflict between the nutrients contained in coffee and milk, and if you add some milk when drinking coffee, you can also adjust the bitterness of coffee and make it taste sweeter. For people with insomnia disorder and poor sleep quality, it is not advisable to drink coffee before going to bed at night, you can drink a cup of warm milk to promote sleep and improve sleep quality. It is recommended that you should not drink too much coffee and milk before going to bed at night, so as not to affect the quality of sleep and increase the number of nighttime awakenings.