How bleeding works
Every injury can make a limb bleed: falls, traps, bites, shrapnel and cuts. Blood volume starts at 5 L. You lose mood as volume drops below 5 L, and your maximum oxygen falls faster and faster as it drops. Below 3 L oxygen capacity drops sharply, which leads to low blood pressure, fibrillation and cardiac arrest.
Skin health limits how fast a limb can bleed. At 0 skin health a limb can bleed up to 1.8 L/min, at 50 skin health 0.9 L/min. Limbs without shrapnel slowly clot on their own, but a limb with shrapnel will not stop bleeding until you pull the shards or bandage it.
Dressings compared
| Item | What it does | How to get it |
|---|---|---|
| Ripped dressing | Weak bleeding fix, crafting material | Rip canvas, bags or cloth |
| Dressing | Slows bleeding about 0.034 L/min per use, +2.5 skin, -5.5 pain, small help to bones | 2 ripped dressings, crates, traders |
| Sterilized dressing | Stops bleeding and disinfects the limb | Craft at INT 7 |
| Plastic dressing | Stronger dressing | Titanium sheet recipe |
| Medical suture | Treats bleeding directly | Loot, traders |
| Clotting mush | Field clotting agent | Craft from blood |
| Tourniquet | Pauses all bleeding on the limb and further out from the torso | Craft at INT 9 |
Restoring skin health also lowers bleeding, which is why bruise kits and dressings both help. Dressings have no effect on muscle health.
When to use a tourniquet
Use a tourniquet when the total bleeding rate under the blood volume meter shows more than about 1 L/min, or when one limb has a dark brown teardrop. It pauses bleeding on that limb and any limb further from the torso. It cannot go on the torso, and on the head it stops your breathing.
- It slowly causes up to 40 pain.
- Natural healing on the limb almost stops while it is on.
- After about 9 minutes, when the icon is fully red, muscle damage starts quickly. Take it off before then.
Blood volume and getting blood back
Blood slowly returns to 5 L at a rate tied to hunger: 0.0525 L/min at 100 hunger, slower as hunger falls, and nothing at 0. That makes food part of blood loss treatment. Fluids work faster:
| Fluid | Use | Watch out for |
|---|---|---|
| Blood bag (your own) | Best refill. Draw blood with an empty bag while healthy, ideally before sleeping (craft at INT 12) | Takes blood away when you fill it |
| Ringer's solution | Volume and thirst | Can thin or clot blood depending on your viscosity |
| Saline | Volume and thirst | Thins blood slightly |
| Human blood | Volume | Can cause sepsis |
Thin blood bleeds faster. Low blood viscosity increases the speed of every bleed: -50% viscosity means +50% bleeding speed. Injecting a lot of miscellaneous liquids lowers viscosity a little each time. Procoagulant raises it. Community wiki
How fast can you bleed out?
At 5 L, losing 1 L/min gives you about 2 minutes before you drop under 3 L, where oxygen and blood pressure start to collapse. At 0.2 L/min you have around 10 minutes. The electronic watch gives a bleed-out estimate, which 1.0 made slightly more accurate. A last stand restores blood volume to 3.75 L, but it only triggers once per run and depends on your mood: see last stand.
Questions
How do you make bandages in Casualties: Unknown?
The basic dressing is crafted from 2 ripped dressings, which you get by ripping canvas or other rippable items. A dressing weighs 0.9u while two canvases weigh only 0.2u, so carry canvas and one dressing, and craft more when needed. Sterilized dressing needs INT 7.
How long can I leave a tourniquet on?
About 9 minutes. The icon fills red over time; once it is completely red it quickly damages muscle on the affected limbs. It also causes up to 40 pain. A tourniquet on the head causes respiratory arrest.
How do I get more blood?
Blood regenerates towards 5 L on its own, at up to 0.0525 L per minute with a full hunger bar and not at all at 0 hunger. To refill quickly, inject a blood bag you filled earlier, Ringer's solution or saline. You can draw your own blood with an empty blood bag while healthy.
Can I use human blood from a red blood bag?
Injecting human blood can cause sepsis, which fades slowly. Red blood bags are used for bio-terminals; transferring the red blood out leaves you a free empty blood bag.
Sources
- Community wiki Blood (volume, pressure, internal bleeding, viscosity) Scav Prototype / C:U wiki, checked 2026-09-21
- Community wiki Injuries (limb and body statuses) Scav Prototype / C:U wiki, checked 2026-10-03
- Community wiki Guide: Getting started Scav Prototype / C:U wiki, checked 2026-07-09
- Official v6.0 patch notes Steam news, checked 2026-04-20