Expired tea is not recommended to drink, the nutritional value is reduced, and at the same time may produce food poisoning and other adverse reactions. Tea itself contains many nutrients, including tea polyphenols, caffeine, vitamin C and other antioxidants, which are beneficial to health when consumed in moderation. However, if the tea leaves are outdated, the nutrients in them will decline, resulting in the oxidation of the antioxidants, thus reducing their nutritional value. Also, with the passage of time, some of the bacteria in it, such as E. coli and Staphylococcus aureus, may be overloaded, leading to bacterial food poisoning. Tea can also produce excessive levels of mold if it is poorly stored. For example, Aspergillus flavus can produce aflatoxin, which is a class 1 carcinogen that can lead to liver cancer, stomach cancer and many other digestive tract tumors, posing a great threat to human health. Therefore, it is generally not recommended to eat expired tea, even if the appearance looks normal, it is also recommended to discard, because there are some deterioration is difficult to identify through the naked eye. Tea must be consumed as soon as possible after purchase, so as not to waste food by expiration, or affect your health.