Hemoptysis

Hemoptysis is a passive item added in The Binding of Isaac: Repentance.

Effects

 * Double-tapping a fire button causes Isaac to sneeze blood, dealing damage to enemies in front of him. The sneeze deals damage equal to 1.5x Isaac's damage and pushes enemies and their projectiles back. If the enemy is pushed into a wall/obstacle, they take 10 damage and deal 10 damage to enemies they collide with.
 * The sneeze has a cooldown of 1 second.

Synergies

 * / /  /  /  /  /  /  /  / : Damage dealt by Brimstone or Brimstone-like beams is doubled on targets that have been sneezed on. The vulnerability is indicated by a faint red tint.
 * The tint is still visible on Champion enemies, and enemies under status effects.
 * : The sneeze will still set enemies on fire, but not cause explosions, similar to its interaction with.
 * : Chance to sneeze in all cardinal directions.
 * : The sneeze reflects enemy shots.
 * : Multiple sneezes are applied around the character.
 * : Shoots two sneezes diagonally instead of one straight forward.

Interactions

 * : The sneeze causes an explosion if used close against a wall or a stationary object.

Trivia

 * Hemoptysis is the medical term for coughing up blood.