Leech is a traditional Chinese medicine. Hot leeches can be used to treat bruises, pain in the heart and abdomen, blood stasis and amenorrhea, and obstruction in the abdomen (the appearance of tangible or intangible lumps in the abdomen, with a feeling of distension and pain) and other conditions. Leeches belong to the liver meridian, with the effect of breaking blood circulation, removing blood stasis and eliminating symptoms. Clinically, leeches are often combined with safflower, peach kernel, gadfly and other traditional Chinese medicines to treat blood stasis and amenorrhea, as well as obstruction of mass in the abdomen. In “Jisheng Fang”, leeches are combined with petunia seeds and rhubarb to treat internal obstruction of blood stasis and pain in the heart and abdomen. In addition, hot leeches can also be used to make bone-splitting fire-dragon dan to improve bruises by combining it with sumac and natural copper. Hot leeches should not be used on women during menstruation, pregnant women, those with bleeding tendency, or those who are weak and have blood deficiency. The medication process should strictly follow the instructions of Chinese medicine practitioners to avoid adverse reactions such as nausea and vomiting, abdominal pain and diarrhea.