A blockhead's physical condition is displayed on its health bar.
A health bar is displayed next to a blockhead's reference icon on the left side of the screen as the upper bar with a red heart on its left. It is also displayed in the menu for eating food as well on a blockhead's full status window.
If a blockhead's health becomes empty, damage is now reflected on the death bar. When the death bar becomes empty, blockheads can die, starting in version 1.5, but they can be regenerated at a portal.
Making a blockhead eat something will usually restore its health as well as relieving hunger.
A blockhead immersed (but not completely submerged) in steaming water will receive a steady increase of health.