Binding of Isaac: Rebirth Wiki

Experimental Treatment is an unlockable passive item.


  • Removed in Afterbirth † Randomly increases at least 1 and decreases 1-3 of Isaac's stats. The same stats can be increased/decreased multiple times.
  • Added in Afterbirth † Randomly increases 4 and decreases 2 of Isaac's stats.
  • Each increase or decrease for a stat will change it by a fixed value:
  • If a stat that is already at an upper or lower limit is chosen, there is no visible effect.
  • Added in Afterbirth This item belongs to the Spun set. Collecting three items from this set will transform Isaac into a buff berserker.


The stat changes are permanent and will not go away if the item is removed.

  • Added in Repentance This makes the item especially useful for Tainted Isaac Tainted Isaac, since he gets to keep the stats while having the option to switch Experimental Treatment for another item and the transformation progress isn't lost in the process.

Added in Repentance The tears up from this item is allowed to go past the normal tear cap of 5.0. However if it decreases tears, the normal tear cap will also be decreased.

In-game Footage[]


Removed in Repentance Prior to Repentance, this item's description was "All stats up... then shuffled".

  • Despite the item's old description, the item did not increase all stats or shuffle them.

Unlockable Achievements[]


PC TTR6 J4D6 (Treasure Room adjacent to spawn)

PC V7F9 GAD3 (Treasure Room south to spawn)

PC Hard mode only 2YN8 JS3R (Treasure Room adjacent to spawn)

PC Added in Afterbirth † Hard mode only 6RPQ N68R (Treasure Room east to spawn)

PC Added in Repentance QAGQ LA07 (Treasure Room adjacent to spawn)

PS4 DMLT 6MM2 (Treasure Room adjacent to spawn)