The purpose of this study is to analyse research trends about medical leech in the last 10 years. Methods: We searched the papers with key words of ‘medical leech’, ‘水蛭’ in China Knowledge Resource Integrated Database (CNKI), Korean traditional knowledge portal, DBPIA, KISS. We classified the papers by year and content. Results: 1. Result of the classification on the basis of the research methods, 50 studies are clinical case reports, 301 studies are experimental paper, 599 studies are clinical trial study, 219 studies are literature review. 2. Result of the classification on the basis of the research topics, 454 studies are the effect of anticoagulant research, 84 studies are diabetes and renal disease research, 194 studies are pharmacological properties research, and 43 studies are effect of allergic and anti-inflammatory research. 3. The proportion of the coagulation effect study tends to decrease every year since 2006. 4. Leech research tends to decrease in last 3 years. 5. Recently, there are many research in psychiatry, orthopedic diseases and beauty. 6. There are 10 studies related to leech in Korean. Conclusions: The researches of medical leech are actively done. The diversity of subjects is getting wider and richer.