Shadow erythrocyte also refers to the erythrocyte shadow, when the erythrocyte contents leak, its membrane can be closed up again and the erythrocyte becomes an empty shell without contents. Erythrocyte shadow is the lipid peroxidation of biological membranes, and there are often pathological and physiological processes that affect the lipid peroxidation of organisms. Pathological processes commonly include chemical poisoning, poisoning by atmospheric pollution, radiation damage, chemical carcinogenesis, hemolytic anemia and smoking. In contrast, normal physiological pathological processes, including phagocytosis and aging, can produce lipid peroxidation.