Health

The health and damage system in Minecraft is based on a simple heart system. Each (full) heart contains two halves.

All player characters and hostile Mobs have 10 hearts at full health, and zero at death. Pigs, Sheep, and Cows all have five hearts, whilst Chickens have two. The effects of damage to your character can be reduced somewhat via the use of Armor.

Damage Inflicted by Player
Players and NPCs can do damage by hitting each other with items at close range. The large majority of items only do ½ a heart of damage, although certain items can be crafted for the express purpose of dealing more. Swords are the main and simplest item to use and make. They still require melee range, but deal significantly more damage per hit.

Besides swords, there are several other unique items that can be used to deal extra damage. Arrows, for example (shot using right click with a Bow), are the only ranged weapon in the game.

Flint and Steel allows the player to light a block on Fire, which causes all players and mobs that walk over that block to be set alight. Players and mobs that are ignited stay alight for 15 hits or until they touch water. Likewise, contact with Lava (say poured from a Bucket) also catches enemies on fire.

Lastly, TNT is currently the only explosive weapon in Minecraft and is consequentially quite hard to obtain.

The below values detail the damage dealt per hit using various items.

Note that using items that aren't intended for combat as melee weapons may cause their durability to be reduced at an accelerated pace.

Damage Inflicted by Mobs
Unlike player character's damage, the damage Mobs do is affected by the difficulty the player is on. The below values represent the amount of hearts taken per hit. Values for the Creeper assume point-blank range.

Natural Damage
Besides mobs, players can take damage from several other events in Minecraft.

Fall Damage
In Alpha mode (and the obsolete indev and infdev modes), you receive damage when falling from certain heights. The amount of damage received depends on the total height of a drop, and it is possible for a player to die upon falling to the ground.

Fall damage can be calculated using this formula:

FD=(number of blocks x ½) - 1½

Mobs (other than chickens) suffer fall damage as well.

In some cases, it is possible to avoid falling or otherwise survive a fall. Falling damage is only dealt after a height of three blocks. Falls equal to or larger than 23 blocks result in an instant death under normal circumstances (23 x ½ - 1½ = 10).


 * Sneaking (default LSHIFT) will prevent you from falling off any ledge in most situations.


 * Having some amount of Armor may save your life from otherwise fatal falls.


 * Landing in Water deeper than two blocks will prevent all damage. If less, then you will still take full damage.


 * Move neutral Mobs away to avoid an unpleasant push to your death.


 * Riding in a Minecart will allow you to leave the scene unhurt.


 * You might not sustain any fall damage while you're on Fire.


 * Jumping counts as falling for 1½ blocks, so keep this in mind when trying to avoid fall damage.


 * Do not mine directly downwards without knowing what is underneath. Empty caverns are randomly placed around the world, and it's quite possible to fall into them (perhaps from a great height, or even onto Lava!).


 * Don't attempt to jump gaps across long drops. Instead, sneak to the edge of your current platform, and you will be able to place a block beside it; in this way, bridges can be constructed safely.

Drowning
Once your air runs out underwater, you will take approximately ½ heart damage/sec. This does not commonly happen to mobs because they automatically float upwards.

While mining, consider keeping at least one placeable solid block ready somewhere on your toolbar (such as Dirt or Cobblestone) for quick access using your mousewheel. If you mine into a spring (or worse, the ocean), you should be able to place the brick in the hole and so prevent drowning.

Suffocation
Occurs when the player's head is somehow inside of solid blocks, most commonly if sand or gravel falls on him (do not mine directly upwards to avoid this, or if that isn't an option, be ready to avoid falling blocks). Causes approximately ½ heart damage/sec. May also occur while riding a Boat or exiting a Minecart under a low space.

Cacti
Touching Cacti will cause a player/mob to take a ½ heart damage, and rapidly continue taking damage if they continue to stand next to/on it.

Lava
By far the most dangerous natural occurrence, players and mobs will take damage from contact with Lava extremely fast (5 points per hit), and stay on fire even if they exit it (½ a point per hit for 15 hits or until extinguished with water). If players do not have a water source available they will die quickly.

While mining, consider keeping at least one placeable solid block ready somewhere on your toolbar (such as Dirt or Cobblestone) for quick access using your mousewheel. If you mine into a lava pool, you may be able to place the brick in the hole and so prevent burning.

It is inadvisable to work near lava while carrying valuable items, as they will be destroyed nearly instantly if they make contact with it (dying causes all your items to be thrown randomly about the area).

Damage Immunity
After sustaining damage from any source, a Mob will turn red in color for a short period of time. During this period, any other incoming damage will not be counted against the mob's total health. For instance, if you attack a mob with a Bow without letting go of the mouse button, the bow's rate of fire will exceed the mob's allowable rate of incoming damage, and several of the shots will not damage the mob even if they land. Arrows that don't deal damage to a mob are reflected off of it onto the ground, and possibly, from a close range, back at the player (resulting in damage). Players are also subject to damage immunity.

Trivia

 * A bucket of lava is arguably the most efficient 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 a large amount of the time the mob's dropped loot will be disintegrated in the lava.
 * If the worst happens and you take enough damage to cause your death, your items will be thrown randomly around the area. Those that touch lava will be near-instantly destroyed. You have five minutes to retrieve other dropped items before they disappear.