The medicinal leech (Hirudo medicinalis) has been used during medical surgery to minimize blood buildup. Due to anticoagulant properties in its saliva, this leech has been very useful for this purpose. Medicinal leeches have been important in research for neurobiology, developmental genetics, enteric symbioses, or oncology (Siddall et al. 2007). There have been at least 115 bioactive compounds isolated from medicinal leeches, includin anticoagulants, antistasins, and other protease inhibitors (Siddall et al. 2007), however it appears that these bioactive compounds are not limited to just Hirudo medicinalis but are also found in additional species of European medicinal leeches (Siddall et al. 2007). Many bioreactive compounds isolated from medicinal leeches are still being researched for their potential; further research will show whether the antimetastatic properties of Hirustasin (isolated from medicinal leeches) are without anticoagulant effects that hinder their use in cancer patients (Sollner et al. 1994).