Microcirculatory disorders are morphological abnormalities and functional disorders of blood vessels and blood flow that occur at the level of the microcirculation. Microcirculatory disorders can lead to a significant reduction in tissue blood perfusion, which can cause a series of ischemic and hypoxic lesions and, in severe cases, organ insufficiency or failure. Microcirculatory disorders often occur in processes such as trauma, inflammation, edema, shock, tumors, superchin reactions, rejection of tissue and organ transplants, and in diseases related to these. What can cause microcirculatory disorders? Bacteria, viruses, physical and chemical factors, as well as secondary changes such as ischemia and hypoxia and acidosis can act on the microvascular wall, causing it to be damaged directly or indirectly. In this case, the earliest reaction is the swelling and separation of the endothelial cells, and in severe cases, the endothelial cells may die into “herpes”-like protrusions, or even the endothelial cells may fall off, thus causing the narrowing of the microvascular lumen and various obstacles to microbleeding. These lesions can severely damage the integrity and extensibility of the microvascular wall, resulting in lengthening, bending, and local expansion of the microvessels to form microangiomas. These lesions can further slow down blood flow, aggravate stagnation, and form pathological microscopic pools of blood locally in the lesion. This is where platelet, leukocyte, or red blood cell aggregation is most likely to occur and “sludge” the microbleeds, contributing to local or systemic disseminated intravascular coagulation. In addition, necrosis of endothelial cells in the microvascular wall, exposure of subendothelial collagen, and contact between plasma and collagen can all contribute to local or systemic disseminated intravascular coagulation. In addition, diastolic vasodilatation and microvascular stasis are also factors that promote or exacerbate microvascular permeability suboptimal. Elevated microvascular permeability is most pronounced in capillary venous rays and microvenules. The result of elevated microvascular permeability is inevitably a large leakage of blood components outside the microvasculature, which can lead to a decrease in effective circulating blood volume and blood concentration, further aggravating microcirculatory disorders. In recent years, Chinese scholars have made careful laboratory observations on severe infectious diseases such as fulminant epidemic meningomyelitis and toxic dysentery, and suggested that acute microcirculatory disorders caused by microarterial spasm are the main pathological changes in the early stages of such diseases, and are the basis for a series of severe symptoms. The pathological changes in microcirculatory disorders are mainly in the microvasculature, microbleeding and microvascular perimeter.