In Jazz Jackrabbit 2, the player‘s health is measured in hearts.

Max health

The player can have seven hearts at most. In all game types, default maximum health is 5, except in CTF, where it’s set to 3 as default.
JJ2+ allow servers to modify this max value.

Losing hearts

When the player is hurt, whether by an enemy, a hurt event, a spike boll or platform, or another player’s weapon or special move, he will lose one or two hearts, depending on what the player hit. For example, touching a Norm Turtle will cause the player to lose one heart, while being hit with a powered-up seeker missile will make him lose two.
A player who loses all his hearts dies: he is roasted.

Regaining hearts

Hearts can be regained by gobbling carrots (for one heart) or full health carrots, for an instant boost to the maximum health.

Hearts look

Hearts are displayed in the top-right corner of the game screen, on one line. Left hearts are lost first.

When the player is down to one heart, it will begin flickering to alert the player of his impending demise.

Fake health

In multiplayer modes, a player may occasionally be hurt, but the heart gauge will not appear to decrease. This is a bug known as fake health.