Shiitake mushrooms are mushrooms and grow faster in a humid and suitable temperature environment. Normal shiitake mushrooms should be brownish in color and moderate consumption helps to strengthen the body and prevent diseases. If the color of the skin of shiitake mushroom turns black, it may be caused by leaving it for a long time after picking, the flesh of shiitake mushroom is no longer fresh at this time, and it is not recommended to eat it. If the mushroom cap folds blacken obviously, it means the fungal spores are mature and the mushroom is about to rot. If the blackened mushroom is accompanied by a strange smell, it means that mold and rot may have occurred, and eating the mushroom at this time may cause food poisoning, so it should be avoided. Blackened shiitake mushrooms may be the result of Aspergillus niger (toxic mold) gradually growing on the surface and inside, which can easily damage important organs and tissues of human body after eating, involving the respiratory system and digestive system, which can lead to lung symptoms such as coughing, coughing up sputum and coughing up blood, as well as gastrointestinal discomfort symptoms such as abdominal pain and diarrhea; when the liver is involved, it can lead to inflammatory reaction to damage liver cells. If the mold enters the blood, it can flow with the blood to all parts of the body and produce sepsis, which can be life-threatening, so it is not recommended to eat blackened mushrooms. If you have eaten blackened shiitake mushrooms, you should observe your health condition and seek medical attention if you have abnormal reactions such as nausea, vomiting, diarrhea, poor breathing, etc. to avoid serious health effects.