Blood stasis is one of the etiological mechanisms in Chinese medicine. There are many causes of internal stasis of blood, including Qi stagnation and blood stasis, Qi deficiency and blood stasis, and blood cold causing stasis. Stagnation of Qi in the liver leads to stagnation of Qi, and stagnation of Qi leads to stagnation of blood, which leads to internal obstruction of blood stasis; deficiency of Qi in the body means that Qi is not enough to run blood, and blood runs too slowly and becomes stagnant; or cold invades the body and clots Qi and blood channels, leading to internal obstruction of blood stasis. In cases of internal obstruction of blood stasis, the skin may be misshapen, with petechiae, painful spots, vomiting blood, hemoptysis and dark blood, dark tongue with petechiae, and thin and astringent pulse.