Upon detonation the Transfusion grenade releases child grenades that slowly seek out targets and explode. Child grenades that do not find a target explode harmlessly after several seconds. Damage triggers the Transfusion effect, turning a portion of damage dealt into life orbs that heal the wielder and allies.
Transfusion grenades are useful for dealing with a both a single, powerful enemy, as all of the child grenades will seek out the single enemy, and for thinning out crowds of enemies. Transfusion grenades are extremely useful for tough fights where health is an issue or for additional healing to relieve pressure on allies dedicated to tanking or healing. Since the child grenades will continue to home in on targets after thrown it is a good tactic to toss out a transfusion grenade if the user is taking heavy damage and expects to become crippled soon. The child grenades have a good chance to kill an enemy and revive the thrower.
Transfusion grenades, including the Kiss of Death and O-Negative grenade mods, are the only weapons manufactured by Maliwan that can deal explosive damage.
Unlike their behaviour in Borderlands, the Transfusion grenade does in fact cause a small explosion upon releasing child grenades, which can damage enemies and playable characters.