For drinking pure milk that has expired for three months, if the pure milk is only past its shelf life but not spoiled, consumption may not lead to discomfort, so you can stop eating it and drink more warm water to accelerate metabolism and promote the early discharge of milk. If the milk has expired and deteriorated, the spoiled milk contains a lot of bacteria and toxins, which may lead to diarrhea, abdominal pain, vomiting, dizziness and other symptoms of food poisoning after consumption. In this case, the expired milk can be expelled from the stomach by inducing vomiting. If the gastrointestinal reaction is more severe, such as severe vomiting, diarrhea, abdominal pain or even fever, it is recommended to seek immediate medical attention to improve the examination and timely treatment.