Cerebral infarction belongs to the category of stroke in Chinese medicine. Leeches, which have a small poison, are usually used after concoction. Leeches are often decocted into soup, pills, powder or minced for the treatment of strokes caused by blood stasis. Leeches have the effect of breaking blood stasis and promoting menstruation, expelling blood stasis and eliminating symptoms. It is mainly used for treating blood stasis and menstrual closure, obstruction in the abdomen (tangible or intangible lumps appearing in the abdomen with distension and pain), bruises and injuries, pain in the heart and abdomen. Adverse reactions: some patients may experience skin rash, itching, nausea, vomiting, abdominal pain, diarrhea gastrointestinal bleeding or even coma after taking it, and allergic persons should not take it. Weakness and blood deficiency, pregnant women, women during menstruation and those with bleeding tendency are prohibited to take. The efficacy of a single Chinese medicine is limited, clinically it is necessary to use with other Chinese medicines after identification by a traditional Chinese medicine practitioner.