Therefore, we must pay attention to the intake of selenium-containing foods. Fish, lobster and some shellfish are rich in selenium. Followed by the heart, liver, kidney and other organs of animals. Vegetables such as shepherd's purse, asparagus, peas, Chinese cabbage, pumpkin, onion and tomato also contain a certain amount of selenium. The bran of grain also contains a small amount of selenium. The intake of selenium must be appropriate. If it exceeds the needs of human body, it may cause pneumonia, liver and kidney function degradation and other diseases. Excessive intake of selenium may lead to death due to chronic poisoning.