To bleed copiously.
To lose (something) in copious and detrimental quantities.
A sudden or significant loss
A heavy release of blood within or from the body.
To perform a phlebotomy; to open a vein to withdraw or let blood.
To perform a phlebotomy on (a vein): to open (a vein) to withdraw or let blood.
To perform a phlebotomy on (a person): to open a vein of (a person) to withdraw or let blood.