Health is the player's life in the game and is represented by hearts at the top of the screen (each heart represents 20 health). Each character starts with 100 maximum health (5 hearts), but that can be increased to a maximum total of 400 (20 hearts) by using Life Crystals. It will take a total of 15 life crystals smashed and used to reach maximum health. When a character's life reaches 0, death occurs.
 Taking damage
The player loses health when they take damage from enemies, environmental hazards, falling or drowning. After taking damage, the player will begin to flash. During this brief period the player is prevented from taking additional damage.
Main article: Enemies
Enemies such as Slimes, Zombies and Skeletons typically deal damage by touching the player. Other, more powerful enemies such as Fire Imps or Harpies can also damage the player via projectiles. Damage from enemies typically inflicts knockback on the player, sending them flying through the air away from the source of the damage.
In addition to enemies, the environment of Terraria itself can cause damage to the player. Spikes and the thorns that grow in the Corruption and Jungle areas hurt the player when touched. The heat from Hellstone and Meteorite blocks will also deal damage to the player. Lava is particularly dangerous as it causes serious damage but does not knock the player back, instead lighting them on fire leaving them to sink further into the lava to take additional damage.
Main article: Fall damage
Falling from a height of more than 25 blocks (50 feet) also causes damage to the player. Falls from greater heights will do more damage than short falls.
Main article: Breath meter
Staying in water for too long will cause the player's health to swiftly drain away due to drowning.
 Preventing damage
By wearing armor and equipping certain accessories players can increase their defense which decreases damage taken. In addition to simply decreasing damage, some items can mitigate or eliminate certain forms of damage. All accessories can have mods that grant up to 4 defense in addition to their other bonuses and functions.
|Shackle||Accessory||Gives the player 1 extra defense.|
|Obsidian Skull||Accessory||Grants immunity to fire-based blocks and gives the player 1 extra defense. This includes Hellstone, Meteorite and Hellstone Brick, but not lava.|
|Cobalt Shield||Accessory||Prevents knockback from damage and gives the player 1 extra defense. By preventing knockback this allows the player to have full use of the brief post-damage invincibility time.|
|Obsidian Shield||Accessory||Combines the functions of the Obsidian Skull and Cobalt Shield. The Obsidian Shield gives the player 2 extra defense.|
|Lucky Horseshoe||Accessory||Negates all falling damage.|
|Obsidian Horseshoe||Accessory||Combines the functions of the Obsidian Skull and Lucky Horseshoe. It does not, however, give any defense.|
|Cloud in a Bottle||Accessory||Allows the player to double-jump. Though this does not directly prevent damage, if used before hitting the ground it can eliminate falling damage.|
|Diving Helmet||Armor||Greatly extends underwater breathing (1 minute and 34 seconds instead of 22 without equipment).|
|Flipper||Accessory||Allows the player to "swim" by jumping while in the water as though standing on a surface. This makes it much easier to avoid drowning.|
|Diving Gear||Accessory||Combines the functions of the Diving Helmet and Flipper. It is equipped in an accessory slot rather than an armor slot, allowing the player to equip a more defensive helmet.|
|Breathing Reed||Item||Allows the player to breathe near the surface of water, and makes the breath meter decrease over a period of 44 seconds(Instead of 22, without equipment). By placing this item on your action bar and selecting it, you will be able to breathe if the top of the reed is above the surface of the water.|
|Grappling Hook||Item||Shoots out a hook that pulls the player to distant ledges. By grappling to a wall or the ground right before landing after a long fall, you can prevent all falling damage.|
|Ivy Whip||Item||An upgrade to the Grappling Hook that shoots faster and can sustain three grapples at the same time. Its role in damage prevention is the same as that of the Grappling Hook.|
|Dual Hook||Item||Arguably a superior form of the Ivy Whip which performs the same role. Additionally, it can fire two hooks at once and provides illumination when attached to a surface.|
|Ironskin Potion||Potion||Increases defense by 8 for 5 minutes.|
 Restoring health
Lost health can be regained in many ways. If the player has access to a Nurse then they can ask her to heal them to full by paying her a fee based on how much damage has been taken. There are also several items that can be used to heal the player. The player will automatically start regenerating health after a short period if no damage has been taken, and it will do it faster while standing still.
|Heart||Hearts restore 20 health instantly when collected and cannot be placed in the Inventory.|
|Mushroom||Restores 15 health when used. Shares a cooldown with most other consumable healing items.|
|Glowing Mushroom||Restores 25 health when used. Shares a cooldown with most other consumable healing items.|
|Lesser Healing Potion||Restores 50 health when used. Shares a cooldown with most other consumable healing items.|
|Healing Potion||Restores 100 health when used. Shares a cooldown with most other consumable healing items.|
|Greater Healing Potion||Restores 150 health when used. Shares a cooldown with most other consumable healing items.|
|Lesser Restoration Potion||Restores 50 health and 50 mana when used. Shares a cooldown with most other consumable healing items.|
|Restoration Potion||Restores 100 health and 100 mana when used. Shares a cooldown with most other consumable healing items.|
|Goldfish||Restores 20 health when used. Shares a cooldown with most other consumable healing items.|
|Life Crystal||Increases maximum life by 20 and restores 20 health when used. Does not trigger the consumable healing item cooldown. Cannot be used if the player's maximum life is at 400.|
|Band of Regeneration||Slowly regenerates health when worn.|
|Regeneration Potion||Regenerates 600 health over the course of 5 minutes.|
|Bottled Water||Restores 20 health when used. Shares a cooldown with most other consumable healing items.|
Note that healing effects will not exceed your maximum health and any healing beyond the maximum is lost. It is advisable to avoid overhealing when healing items are scarce.
Almost all consumable restoration items are affected by a shared consumable healing item cooldown, excluding the Regeneration Potion. The cooldown is 60 seconds long and begins when a consumable healing item is used. During this period the player is not allowed to consume any more consumable healing items. This prevents players from bypassing hazardous areas, enemies, or surviving long, difficult battles through constant item consumption.
|Attack Speed • Breath meter • Buffs • By hand • Consumable • Crafting station • Critical hit • Damage types • Data IDs|
Day and night cycle • Death • Debuffs • Defense • Difficulty • Environment • Fall Damage • Game controls • Ghost • Health • Inventory
Knockback • Lighting mode • Mana • Map Size • Modifier • Moon phase • Music • NPC drops • NPC Spawning • Placement
Player stats • Rarity • Shoot speed • Spawn • Storage items • Use time • Value