Milk is not recommended to be consumed for health reasons if it exceeds the shelf life by a few days. If it exceeds the shelf life for too long and deterioration occurs then it should not be consumed in order to avoid health hazards to the organism. In general, the shelf life is the best time to drink milk. After the shelf life is exceeded, the nutritional value in milk will be reduced and microorganisms such as bacteria and viruses that are not visible to the naked eye may be produced, which may have an effect on the organism. Especially patients with weak spleen and stomach or poor resistance may experience gastrointestinal reactions such as abdominal pain and diarrhea after drinking expired milk. Therefore, it is recommended that milk beyond its shelf life should not be consumed again as much as possible, not only the nutritional value of intake will be reduced, but also other adverse reactions may occur. If the milk has precipitated, become tasteless or otherwise deteriorated, even if it has not reached its shelf life, it is not allowed to continue to drink it, and it is recommended that the milk be stored in a suitable temperature and environment to avoid deterioration. If patients experience abdominal pain, diarrhea, nausea, vomiting and other gastrointestinal symptoms after drinking expired milk, it is recommended to go to a regular hospital for treatment.