Adverse reactions such as nausea, vomiting, abdominal pain, and even intestinal bleeding, skin redness, swelling and itching may occur when leeches pass through blood vessels. Leech is a traditional Chinese medicine, which has the effect of removing blood stasis and eliminating the symptom (hard lumps in the abdomen) as well as breaking the blood and promoting menstruation. It can be used in cases of bruises, blood stasis and menstrual closure as well as pain in the heart and abdomen, and obstruction of obstruction in the abdomen (the appearance of tangible or invisible lumps in the abdomen, with a feeling of distension and pain). Its adverse reactions are itching, redness and swelling of the skin, nausea, diarrhea, vomiting, abdominal pain in some patients, and coma and gastrointestinal bleeding in severe cases. It should be noted that it is forbidden to be taken by people with bleeding tendency, women during menstruation, pregnant women and those who are weak and blood deficient. If you need to use this medicine, it should be used under the guidance of a Chinese medicine practitioner’s diagnosis, and should not be used on its own to avoid causing adverse consequences.