Leeches – great for venous congestion, and as pets?

Apparently some 'pet' owners are feeding them their own blood

Patients are often startled to learn that leech therapy is used in modern medicine — and that, oddly, they’re listed with regulatory authorities as ‘medical devices’.

Live blood-suckers are deployed to benefit patients undergoing reconstructive surgery to ease venous congestion, while alternative medicine practitioners tout them for a variety of indications.