Erythrocytes can be characterized in terms of structure and function. 1. Structure: Mature erythrocytes have the shape of a double-sided concave disk, thin in the center and thick at the periphery, and this special structure can increase the body surface area of erythrocytes. Mature erythrocytes do not contain Golgi apparatus, nucleus, mitochondria, and can carry more hemoglobin. 2. Function: Hemoglobin contained in erythrocytes combines with carbon dioxide and oxygen to transport carbon dioxide and oxygen. Hemoglobin binds more easily to carbon monoxide and is not easily separated after binding. When the carbon monoxide level in the air is too high for a long time, it can lead to carbon monoxide poisoning. Red blood cells can also enhance phagocytosis, play the role of immune adhesion and prevention of infection, which can enhance the body’s immunity. Red blood cells are very important to our body, abnormal increase or decrease will affect our health, the specific treatment should be carried out under the guidance of physicians.