Blood stasis refers to a type of evidence in TCM diagnosis. Blood stasis means that the blood is not running well and there is blood stasis. Blood stasis can be seen in many kinds of diseases. Generally speaking, where the blood leaving the meridians cannot dissipate in time and stagnate in a certain place, or where the blood flow is not smooth, the operation is blocked, and the blood accumulates in the meridians or organs in a state of stagnation, all of them are called blood stasis. The pain is like a pinprick or a knife cut, the pain has a fixed place and refuses to be pressed, and it is often aggravated at night. Lumps on the surface of the body, the color is blue and purple; in the abdomen, hard and hard to press and do not move, also known as scar accumulation. Bleeding is recurrent and purplish in color, or stools are as black as tar. The face is sallow, the skin and nails are wrong, the lips and claws and nails are purple and dark, or there are purple spots under the skin, or the skin has tiny blood veins like wisps, or the abdominal veins are exposed, or the lower limbs are bruised and swollen. Menorrhagia is common in women. The tongue is purple and dark, or petechiae are seen, the pulse is fine and astringent, in short, characterized by pain, purple, petechiae, lumps and astringency. Blood stasis is also often referred to as bruising. The original meaning of stasis refers to the accumulation of blood that does not work. For example, “Shuowen Jiezi” explains: “Stasis, accumulation of blood is also”. Dictionary: “Stasis, accumulation of blood. That is, blood stasis. It means that the blood in the body is stagnant in a certain place”. Silt, originally refers to the sediment in the water, but also has the meaning of “stagnation, non-circulation”, “Dictionary” said: “Siltation, accumulation of blood of the disease also” “blood stagnation, also known as the” Siltation of blood “. The meaning of “stasis” in Chinese medicine has the following four aspects. First, the blood does not act as stasis. Blood travels through the veins and should circulate without stagnation, but if it is affected by various disease-causing factors, resulting in the accumulation of blood, or blood overflows outside the veins and fails to be discharged from the body, it is stasis. Secondly, the blood does not flow smoothly as stasis. Blood should flow freely, but under the effect of various disease-causing factors, the blood cannot flow freely through the veins and channels, i.e., the blood flow is blocked and the blood flow is stagnant, which is also called stasis. At this time, the stasis refers to a pathological state in which the blood circulation is slow and not smooth. Third, the blood that leaves the meridian is stasis. Blood that has left menstruation is not beneficial but harmful to the body. The Treatise on Blood Evidence says: “The world says that blood clots are stasis and clear blood is not stasis; black color is stasis and fresh blood is not stasis; this theory is not true. Covering the blood at the beginning of the menstruation, clear blood, fresh blood, but that is the blood from the menstruation, although clear blood, fresh blood, is also stasis. In addition, in the process of modern Chinese medicine research, people have assigned new meanings to “stasis”, such as “blood stasis evidence and blood stasis research” book pointed out that: “the concept of stasis, in addition to including blood ‘stasis’ or ‘blood stasis’. In addition to blood ‘stasis’ or ‘blood stasis’, the concept of ‘stasis’ should also include ‘stasis’ of qi, i.e., ‘qi stasis’ or ‘qi stagnation’. “. The Treatise on Qi and Blood also points out that “Stasis is not exclusively referring to blood stasis. All the symptoms caused by tangible evils that block the channels and veins can be collectively called siltation”. At this time, the meaning of stasis (or sludge) is quite broad, but always with stagnation and unimpeded as the fundamental link.