Allergy to drinking milk powder is a common allergic reaction to drinking pure milk, so it is recommended to choose carefully to drink it. Allergy from drinking milk powder belongs to exogenous allergy, which means that certain substances in milk powder will be regarded as foreign harmful substances by the human body, and the immune system of the human body will repel or eliminate them to realize the function of protecting the human body. Therefore, when the body encounters these substances again, certain symptoms such as redness, swelling and pain will occur. The main cause of allergy to milk powder is allergy to cow’s milk proteins, of which casein, β-lactoglobulin and α-lactalbumin are considered to be the most important allergens in cow’s milk. Pure milk generally contains these substances, so if you are allergic to cow’s milk proteins, you may also be allergic to drinking pure milk. However, because the ingredients in milk powder are more complex, in addition to cow’s milk protein, it also contains more lipids, vitamins, minerals, and even some common additives and excipients. If you are allergic to the excipients in the milk powder, you may not be allergic to it when drinking plain milk. For this reason, it is necessary to identify the allergens to which an allergy occurs in order to better evaluate the possibility of consuming pure milk.