Oysters are a delicious seafood, seafood in the food is very popular, because the taste is very delicious, and eat not easy to cause greasy feeling. But oysters can also cause certain side effects when eaten in excess, as follows: 1, gastrointestinal discomfort: oysters themselves are high in cholesterol, if consumed in large quantities, will bring more burden to the gastrointestinal, easy to affect the speed of digestion, so for the three high people, must stay away from oysters; 2, immunity is reduced: oysters in the zinc, selenium content is more, normal consumption of 1-2 oysters can be supplemented with these elements, if eaten in large quantities will be counterproductive. If consumed in large quantities, it will be counterproductive. Excessive zinc will inhibit the phagocytosis of cells, the ability to kill bacteria will decline, and immunity will naturally become worse, so for the health of the body, you must eat oysters in moderation; 3, diarrhea: oysters are cold food, once a large number of consumption will hurt the gastrointestinal, easy to cause diarrhea, especially for people with poor gastrointestinal function, the consumption of oysters should be moderate; 4, increase the metabolic burden on the kidneys: Because oysters are rich in protein, and the metabolism of protein requires the participation of the kidneys, if too much intake of oysters and cause excessive protein intake, increasing the burden on the kidneys, which may lead to edema; 5, increased blood pressure: patients may be too much intake of oysters which contain salt, and cause an increase in blood pressure, because oysters are rich in certain sodium elements, sodium elements Sodium can cause sodium retention and increase the amount of fluid in the body, which in turn can lead to an increase in blood pressure, causing a high incidence of cardiovascular disease.