Yes, they have valuable uses in medicine, until we find a better substitute at least. http://www.pbs.org/wgbh/nova/body/leeches.html http://www.pbs.org/wgbh/no

Yes, they have valuable uses in medicine, until we find a better substitute at least. http://www.pbs.org/wgbh/nova/body/leeches.html http://www.pbs.org/wgbh/nova/body/leeches.html There is a mechanical leech but it doesn't work as well at the moment and there's no real downside to using real leeches.