Health, in general, measures how much damage you can take before dying. If the sum of your damage lowers your health to 0, you will fall in critical status. Further damage will lower health into negative numbers; you'll die if you reach the opposite of your max health.
Health is not precisely visible normally; all you have is a green pulse that gets redder and smaller when you get hurt. You will also have a Health Doll, which shows which limbs have been hurt. To heal from damage with brute packs or ointments, you'll have to target the hurt limbs first.
Health Analyzers can be used to obtain a detailed readout of the health of a humanoid, showing precisely how much of each type of damage has been taken, and where. It will also tell in broad terms if the target is suffering from special damage types.
Health Scanner HUDs are a special type of glasses that will show a lifebar on top of all living beings. The bar will go from full to empty when going from alive to crit; when in crit, the bar will start flashing red, with the flashes becoming more frequent as the target approaches death.
By default, humans and humanoids have 100 health (and consequently up to -100 crit health).
Most humanoids have blood. The base amount is 560cc, which generally remains at that level. Blood can be drawn and injected with syringes and IV drips, can be lost from wounds and regenerated through chemicals. Blood regenerates slowly over time, and regenerates faster the better fed you are.
There are also blood types, which follow the general real world rules. Lizardpeople have a special bloodtype, marked L, which can only receive from and donate to the L blood type. See the table below to see which blood types can receive which. Red is the donor.
To restore lost health the specific type of damage dealt must be fixed. If you take 40 total damage of any types you get slowed down.
Main Damage Types
There are five types of damage that affect your overall health (HP), and some other forms of damage which does not directly harm it. See the Guide to medicine for suggestions on how to heal different types of damage.
Brute damage is the most common: it's caused by being hit with physical weapons, pressure or lack thereof, explosions, acid, surgery, and so on.
A side effect of brute damage is Bleeding: once you take enough brute damage, you'll start bleeding out in proportion to the damage taken. Bleeding can be noticed by drops of blood falling off your character periodically.
The second most common damage, Burn damage is usually dealt by lasers, hot weapons like welding tools, electric shocks, explosions, and fire. Damage dealt by cold is also taken as burn damage.
Burn damage cannot cause bleeding, but corpses affected by enough burn damage become Husks, becoming hard to identify and to clone.
The least common (normal) damage is Toxin damage. It's caused mainly by, obviously, toxins, and miscellaneous poisoning.
Unlike burn or brute damage, toxin damage leaves no physical marks, making it invisible to bystanders examining you. It can still be detected by using a Health Analyzer. You can't directly detect the presence of toxins on yourself without one either, but you can usually tell by checking the health bar on the health scanner HUD, or from the fact that you are slowed down without being hurt in other ways.
Also known as suffocation, or oxyloss, oxygen damage is taken when not breathing, or by some special toxins.
Oxyloss, unlike other forms of damage, will heal quickly over time if you're breathing, making it generally not too threatening on its own. However, it still counts as normal damage when calculating crit and death, so continued lack of breathing will still end up being lethal. If you take 50 or more suffocation damage, you pass out.
Accumulating too much oxygen damage also causes you to occasionally pass out, making it harder to get to a safe spot or acquire internals.
Cellular damage (also referred to as cloneloss or clone damage) is a special type of damage which is hidden even from Health Analyzers, although it will still factor into the health total, which means that subtracting the other damage from the total health will let you figure out the total cellular damage.
The most common source of cellular damage is cloning: clones will start with heavy cellular damage when they get out of the pod. Other sources are slimes, which are rarely seen unless you work in Xenobiology.
Special Damage Types
Stamina damage (also called holodamage) is basically "fake" damage: it will change your health icon as if it was real damage, but it's not calculated for crit or death. If you gain over 40 stamina damage you get slowed just like with normal damage. However, if chest or head get 100+ stamina damage, you'll get inflicted with a special variety of paralyze for some time, a stamcrit version which works separatedly from ordinary paralyze. This paralyze can not be reduced with "stun time reduction" chems or abilities, but stun immunities will still make you immune to it. The moment you enter stamcrit you take 30 extra stamina damage. Maximum stamina damage to chest is 120. Stamina does not stack with normal damage when calculating slowdown and stamcrit thresholds.
Limbs can take stamina damage too. If a limb takes over 50 stamina damage it will become disabled until it regenerates. Limbs only take 75% stamina damage.
Stamina damage will be instantly purged 10 seconds after last time you took such damage. Your stamina-critical state (paralyze) will also end if you regenerate to under 100 stamina damage.
By itself it does nothing, but taking brain damage has a chance of inflicting Brain Traumas. This chance scales both with the amount of damage taken by the hit and the brain damage you already have.
If brain damage reaches extremely high levels (200 hp) you'll die of brain death, with no possibility of cloning as the brain becomes unusable. You can still fix this by splashing some Mannitol on the brain. It will heal its damage instantly.
Bleeding is generally caused by brute damage, and rarely by embedded objects or heparin. When bleeding, your blood volume decreases over time. When it starts getting low, you'll start seeing messages like "You start to feel tired...". If it gets even lower, you'll start rapidly taking oxygen damage, proportionally to the amount of blood lost.
If your blood volume gets too low, you'll die even if you managed to stave off the oxygen damage.
Radiation can be accumulated through genetics testing, radiation storms, staying too close to the supermatter or the nuclear fission device, fusion and its nuclear particles as well as hot tritium (probably due to atmos techs), or by certain weapons and traitor devices. Items exposed to radiation can themselves become sources of radiation (even things like air alarms and plasma windows).
Radiation will gradually deal toxin damage. Additionally, it can cause complete hair loss, random mutations, fainting, and vomiting.
Ear damage is caused by loud noises like flashbangs, or diseases. Enough ear damage will result in deafness.
Eye damage is caused by stabbing eyes with sharp items, bright flashes from flashbangs or explosions, or diseases. Eye damage will result in eye blurring, nearsightedness, and eventually total blindness.
Also referred to as Crit, critical status happens when you fall below 0 health. This essentially means that you are barley alive, and are on the verge of death. Reaching this means you you will most likely require assistance from another crewmember to have a chance of living.
There are two kinds of critical status, which are nicknamed Softcrit and Hardcrit. After losing around 100 hp (changes depending on mood) you enter softcrit. You are severely hurt and are close to passing out; all you can do in this state is slowly crawl and whisper, which can help you hide or get away to saftey.
After reaching -50 HP, you will enter Hardcrit. You are still technically alive, but you are effectively helpless: you'll be deaf, mute, blind and unable to move or act. You'll also start slowly suffocating, meaning that eventually you will die if nobody saves you. Whispering (.w) while in hardcrit will allow you to whisper a short message in your last breath to those who are close to you; however, doing so will kill you instantly.
Deathgasp (*deathgasp) can also be used while in crit (or at anytime). It's an emote that mimics your death message, which may fool bystanders (or your killer) into thinking you died, buying you some time.
The final stage. This occurs once you've reached -100 health. You are completely unable to do anything in this stage and will have to wait to be revived. You're allowed to leave your corpse and go spectate as a Ghost but be aware that if someone attempts to revive you you'll have to manually enter your corpse to come back to life.
Otherwise, enjoy spectating the round as a Ghost, or take one of the Ghost Roles. There are also special opportunities and events where ghosts can enter a round again as another role or antagonist. All of these are separate lives, and you cannot use knowledge gained in a previous life while playing them.
Simple animals handle health in a simpler way: They have a health value, which is displayed to the player as a percentage in the Status tab on the right. Any damage taken will lower the health value, which in most cases can be healed by bruise packs, or in rare cases self-healing.