Adds a 25% chance to drop a full Red Heart upon taking damage.
Adds a separate 10% chance to gain the Anemic effect (+5 range, red creep trail) for the current room upon taking damage.
Taking damage will cause Isaac to bleed, spewing blood tears around him constantly.
Holding a direction of fire focuses the bleeding tears to that direction, with slightly increased range.
The bleeding tears can be aimed at any direction just like having Analog Stick.
After bleeding for 20 seconds, Isaac's Red Hearts or Rotten Hearts will take damage (bypassing other Hearts); this is indicated by Isaac slowly turning red after and eventually blinking. This damage also has a 25% chance to drop a full Red Heart. The damaging effect will continue to occur every 20 seconds until the bleeding effect ends.
The damage amount is always half a Red Heart, a Coin Heart, or a Rotten Heart, even in later chapters where most damage is now a full Heart or two Rotten Hearts.
The bleeding effect ends when Isaac receives any form of Red Heart or Rotten Heart healing, if he has no more Red or Rotten Hearts, if he fills an Eternal Heart, or if the next hit would kill him.
If Isaac has no Red or Rotten Hearts, the bleeding effect of Shard of Glass will not activate.
Notes
Red Hearts spawned by this item may become different hearts in certain Super Secret Rooms.
Red Hearts become Soul Hearts in the Cathedral room theme.
Red Hearts become Black Hearts in the Dark Room and Library room theme.
Red Hearts become Rotten Hearts in the Corpse room theme.
Taking bleed damage will not affect Devil/Angel room chance.
Bleeding blood tears will not keep any tear effects or special tears that Isaac have.
The bleeding effect carries over to the next floor if Isaac moves on to the next floor while still bleeding.
If Shard of Glass is re-rolled or lost while Isaac is bleeding, the bleeding will continue, but Red Hearts will no longer spawn when Isaac takes damage. This makes Shard of Glass especially deadly toTainted Eden with a red-heart build.
The bleeding effect works with Keeper and Tainted Keeper. They will bleed and lose a coin heart until only one coin is left. Receiving coins will stop the bleeding effect. Due to Tainted Keeper only having two coin hearts in most circumstances, bleeding will rarely apply to him.
Rotten Hearts will take bleeding damage only when Isaac has no red hearts remaining. Picking up Rotten Hearts will also end the bleeding.
Using a bed or a Full Health pill to heal Isaac's red hearts will not stop the bleeding.
Red Heart upon taking damage.
Adds a separate 10% chance to gain the 
Anemic effect (+5 range, red creep trail) for the current room upon taking damage.
Taking damage will cause Isaac to bleed, spewing blood tears around him constantly.
Analog Stick.
Rotten Heart, even in later chapters where most damage is now a full Heart or two Rotten Hearts.
Eternal Heart, or if the next hit would kill him.
Super Secret Rooms.
Tainted Eden with a red-heart build.
The Forgotten can end the bleeding by switching to 
The Soul.
Keeper and 
Tainted Keeper. They will bleed and lose a coin heart until only one coin is left. Receiving coins will stop the bleeding effect. Due to Tainted Keeper only having two coin hearts in most circumstances, bleeding will rarely apply to him.
White Fire Place or 
Soul of the Lost will stop bleeding effect.
Yum Heart will stop the bleeding effect.
Epic Fetus / 
Marked: Bleeding tears will aim at the crosshair.
The Ludovico Technique: Bleeding tears will aim at the controlled tear.
Blood Donation Machine as the cause of death.
The Binding of Isaac: Rebirth
