Drinking expired yogurt may not cause symptoms, but it may lead to bacterial food poisoning or excessive intake of other harmful substances. The shelf life of yogurt is relatively short, and expired yogurt is prone to bacterial growth, such as Staphylococcus aureus and Escherichia coli, etc. Drinking it may cause gastrointestinal reactions such as nausea, vomiting, abdominal pain, diarrhea and other gastrointestinal adverse reactions, and produce bacterial food poisoning. Some of the proteins in expired yogurt have been spoiled, so it does not provide rich nutrients after drinking. Part of the spoiled protein will release such as amine, ammonia, phenol, indole, hydrogen sulfide, methane, methyl indole and other harmful substances, histidine decomposition to generate histamine, but also may lead to itching, skin rash, breathing difficulties and other histamine poisoning reaction. If you drink expired yogurt symptoms are serious, you need to go to the hospital in time to do the examination.