I thought a challenge room would open on full heart and it is as well not a boss challenge room. The door seems to be open when I enter but immediately closes.

Is it because I have picked up IPECAC?

Locked challenge room

  • Why is this tagged as both binding-of-isaac and binding-of-isaac-rebirth? You can tell from the screenshot that it's not Rebirth.
    – Powerlord
    Oct 18, 2015 at 23:42
  • I've removed the wrong tag, although it's a suitable question for Rebirth, too. The answer is the same for both games.
    – pinckerman
    Oct 19, 2015 at 1:27

2 Answers 2


This room is a boss challenge room, as denoted by the skull inside the swords, to enter it you need one heart or less of red hearts left, meaning that soul hearts do not count.

For more info here's the wiki page

  • 2
    @user4000599 so this is the right answer, would be nice if you mark it so we can close this question
    – Iceag
    Oct 19, 2015 at 8:50

The room appears to be a boss challenge room, indicated by the skull above the door. Additionally, the sword icon on your minimap has blood on it, which is also an indicator that the room is a boss challenge room.

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