Hirudo

leech genus

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 17, 2026

Quick Summary

The genus Hirudo refers to specific species of leeches, most notably Hirudo medicinalis, H. verbana, and H. orientalis. These leeches, commonly known as medicinal leeches, are segmented worms belonging to the phylum Annelida. They are characterized by a small sucker at the anterior end containing the mouth and a larger sucker at the posterior end.12

Historically, medicinal leeches were used to treat various human ailments. Currently, they are utilized as a source of anticoagulants, particularly hirudin, which is used to prevent blood clots after certain surgical procedures. Leeches possess a digestive system with a crop that can store food for extended periods, and they are hermaphroditic, meaning each individual has both male and female reproductive organs.12

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

4 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

annelid
Annotated classification
…20 cm; examples of genera: Hirudo, Haemopis, Erpobdella. Most authors accept the annelids as having three major classes: Polychaeta, Oligochaeta, and Hirudinea. Older systems would place the polychaetes and oligochaetes under the class Chaetopoda because both groups possess
Read More
…20 cm; examples of genera: Hirudo, Haemopis, Erpobdella. Most authors accept the annelids as having three major classes: Polychaeta, Oligochaeta, and Hirudinea. Older systems would place the polychaetes and oligochaetes under the class Chaetopoda because both groups possess
Read More