Health

The health gauge and monitor in Minecraft is based on a single row of 10 heart icons. Each full heart contains two halves, one hit point each (full health is 20 hit points).

Hearts
Hearts make up the health meter for the player and mobs in the Survival, Hardcore, and Adventure modes. Each heart represents two hit points, for a total of 20 hit points. Hit points are lost as a percentage of those hit points. As it appears on the health bar, you lose 1 point (half heart) at a time.

Hit points can be lost by: starving; taking fall damage; being attacked by a hostile mob (or another player if PvP is on); being shot with an arrow; being on fire; touching lava, fire, or a cactus; drowning underwater; suffocating inside a block; falling into the void; having certain status effects, or getting caught in an explosion. When the health meter shows two hearts or less (20% or less health), it will begin to shake violently, warning that the player's demise is imminent if health is not restored.

Health can be recovered through several means, both "naturally" and through status effects such as potions provide.
 * The "instant health" potion effect will restore health immediately, the amount depending on the source and effect level.
 * On Peaceful difficulty, the health meter will continuously refill over time.
 * On other difficulties, health regenerates slowly when the player's hunger is at or above
 * The player will lose health when the hunger is
 * The "regeneration" effect makes health regenerate fairly quickly. Aside from potions of regeneration, this is also provided by beacons and golden apples.  The "basic" golden apple provides it (level II) only for 5 seconds, restoring a total of .  The "enchanted" golden apple provides it for much longer (30 seconds) and at much higher level (level V, over eight times the healing speed of the basic golden apple)and in total restoring about .  (These numbers are as of version 1.6, when both their effects and the speed of regeneration were adjusted.)
 * The "health boost" effect adds per effect level to the players total health, which is removed when the effect expires.  After the effect expires, the player's health may remain above the normal maximum, but the extra health will not be recovered once lost to damage.  This effect can only be gained through "cheat" commands, prepared command blocks, or mods. At the maximum level of 255, the player has 522 hearts.
 * The "absorption" effect likewise adds for each effect level.   This special health cannot be healed or regenerated by normal means, but will be automatically restored every 30 seconds, regardless of the rest of the health bar. Naturally, it will be removed when the effect expires.  As of version 1.6, the absorption effect can be gained by eating either type of golden apple.

Damage is split between the health and Armor bars. Each full armor point takes 8% of damage, to a maximum of 80%, rounded up.

On Hardcore mode, hearts have a different texture

In Creative mode the player still has health, but it is hidden from the interface, and the player is invulnerable to everything except falling into the Void or the /kill command. In Pocket Edition, health can be restored with food.

Armor


Armor is a craftable item that can be worn in Minecraft's survival mode and survival mode multiplayer that reduces damage to the player while also decreasing the armor's durability. Armor can currently be crafted out of Diamond, Iron, Gold and Leather.


 * Zombies and Skeletons would occasionally wear armor in Survival Test. This armor, however, did not alter any of their stats, and was purely superficial. In 1.4, Zombies and Skeletons can wear armor when spawning, and can pick up armor off of the ground when the player dies or drops the armor.
 * Chain Armor is also craftable, but only by using fire blocks, which cannot be obtained without inventory editing, mods, or the command, by which you would use  (this no longer works as of 14w25a). In survival mode it can be obtained by Trading with a Villager or as an uncommon drop of a skeleton or zombie wearing Chain Armor.

Death


Death occurs when all of a player's hit points are depleted. A "You died!" screen will appear with the player's score displayed (before Beta 1.9pre2, it had &e0 as the score), and the player has the option to respawn at the spawn point (either the last bed the player slept in, their default spawn point (their first spawn point in the game), or a spawn point created by commands) or return to the title Menu. In Hardcore Mode, the player cannot respawn and the world will be deleted. Any items and/or blocks that were in the player's inventory are dropped from their head and scattered around the spot where the player died. If they come in contact with dangerous blocks - like lava, fire or cactus blocks - they will be destroyed. Otherwise, according to Notch, "they decay after five minutes, except if the chunk is unloaded, in which case they last forever". The player will also lose any experience accumulated reverting the level back to 0. (xp can also be picked up where the player died.)

Mobs fall sideways to the ground when killed, as shown in the image. The player also falls sideways when killed. In Pocket Edition, when you die, your screen is tilted simulating a broken neck and it infinitely zooms in.

Trivia

 * A bucket of lava is arguably the most effective weapon in the game, as it doesn't use up durability, does very fast damage, and slows enemies in their tracks. The only downside is that most of the time the mob's dropped loot will disintegrate in the lava. It may also cause nearby trees or wooden buildings to catch fire, possibly even starting vast fires, also it may backfire if the user is hit by the lava and is messy to clear up after use.
 * Transparent blocks will not cause suffocation. As a result, placing a slab above a minecart track can be used to make a barrier through which carts can be ridden without allowing mobs (other than 1 block high Chickens, Pigs, tiny Slimes, Silverfish, Cave Spiders, Bats and Wolves) to wander in.
 * Using a trapdoor functions similarly, in addition to being able to open the door to pass through on foot.
 * Players deal Critical hits when falling (losing altitude).
 * There's a bug that when you die, your skin reverts to the default skin during the death animation. This can be seen by your inventory moments before death or being in 3rd person view.
 * When falling, the player's terminal velocity (the fastest speed one can fall at) is theoretically 78.4 m/s (282 km/h), but in fact there isn't enough height to reach that velocity—falling from layer 256 to bedrock, they only have time to reach 70 m/s (253 km/h).
 * Mobs give different death messages, and so do certain other things. There is the standard message of "Player was slain by X", shooting message, like "Player was shot by Skeleton/Player", a message for when the player dies of fall damage, if the fall damage was a direct result of the mobs attack; "Player was blown from a high place by Creeper" or "Player was knocked from a high place by (mob other than Creeper)". If the player takes the mob's normal form of damage and fall damage within a few seconds of death, the message is "Player was (knocked) from a high place and got finished off by Mob".