In general, the black part inside the oyster is edible. Oysters are a food with high nutritional value and the rest of them are edible except for the shell which is inedible. The black part inside the oyster is the digestive system of the oyster, which is mainly seaweed, organic matter and other foods that have not yet had time to be digested, containing protein, zinc and other nutrients, and can be eaten under normal circumstances. However, if the farm waters are polluted and may be enriched with pollutants in the digestive system of oysters, it is not recommended to consume the black part of the oyster to prevent harm to humans. For most people, oysters are good for the body. Oysters contain the amino acids that the body needs and are low in fat and cholesterol, making them a nutritious and healthy delicacy. However, when consuming oysters, you need to pay attention to: 1. People with seafood allergies are cautious to eat oysters, which are also a type of seafood, and people who are allergic to other seafood have a high chance of being allergic to oysters. If symptoms such as itchy skin, rash and red spots appear after eating oysters, you should go to the hospital in time, and those with serious symptoms should be prohibited from eating oysters; 2, people with gastrointestinal discomfort should not eat oysters, people with gastrointestinal discomfort have a reduced resistance to bacteria, and eating oysters may aggravate gastrointestinal discomfort; 3, patients with hyperuricemia are not suitable for eating large amounts of oysters, because the purine content of oysters is high, and eating them may aggravate gout 4, try not to eat raw oysters, oysters in the process of growth may have a variety of bacteria, parasites and other substances harmful to the human body, raw food easily lead to parasitic infection and gastroenteritis and other gastrointestinal diseases.