Build 42 First Aid Guide — Treating Wounds, Infection & Broken Bones on 42.20

Your first week in Build 42 is decided by how you treat a scratch. First aid in Project Zomboid is a real medical loop: clean the wound, bandage it, keep the bandage clean, and know which wounds heal and which do not. The one rule that never changes — a zombie bite is 100% fatal and no first aid stops it — but everything else (scratches, lacerations, deep wounds, fractures, burns, glass and bullets) is very much treatable. This guide covers the 42.20 treatment order and the items that matter.

The treatment order (Health Panel)

For any bleeding wound, the order matters more than the supplies:

1. Stop the bleeding with a bandage (clean if you have one).
2. Disinfect first — apply disinfectant/alcohol to the wound, then bandage it. This is the step most players skip, and it is the one that prevents wound infection.
3. Change dirty bandages — a bandage turns dirty and then bloody; dirty bandages cause infection. Replace them on schedule from the Health Panel.
4. Remove foreign objects (glass shards, bullets) with a needle/tweezers before bandaging — leaving them in stops healing.

The Health Panel shows each wound with its own timer and condition, and it is the same screen that auto-applies first-aid items when you have the right skill.

Wound types in Build 42

Wound infection vs the Knox virus

There are two different "infections" and confusing them kills people:

• Wound infection — a bacteria infection from dirty bandages or dirty wounds. It slows healing, increases pain, and eventually kills if ignored, but it is treatable: clean the wound, replace bandages, use sterilized bandages. Do not confuse it with the virus.
• The Knox infection (zombie virus) — a bite transmits it with certainty, a scratch/laceration with a small chance. It is always fatal; the first symptom is the "Queasy" moodle a few hours later, then fever. First aid, antibiotics, vitamins — none of it cures the virus. Its only value after a bite is palliative care (painkillers/sleep) so the last days are comfortable, and writing your will for the next character.

If the Health Panel shows a wound but the character is not queasy, it is wound infection — treatable. Queasy + a fresh bite means the end of that character, full stop.

Essential first-aid items

First-aid kits now come in tiers (ordinary, camping, military) with different capacities — the military kit holds the full surgical set and is the one worth hoarding.

First Aid skill leveling

The First Aid skill makes every step above better: cleaner bandaging, lower infection chance, faster recovery, and automatic item use from the Health Panel. Fastest XP routes on 42.20:

• Bandage a lot (and remove bandages). Every dressing/redressing grants XP — split a stack and reapply repeatedly in safety.
• Use proper supplies — sterilized bandages and disinfectant give more XP than improvised cloth.
• Treat teammates in multiplayer (huge XP per patient).
• Combine with the Nurse occupation (+3 First Aid) and the First Aid trait for the fastest start — details in the skill leveling guide.

Verified on 42.20 · Last checked 2026-08-05

Wound types, treatment order, kit tiers and skill XP sources from pzfans.com's Build 42.19 first-aid guides and first-aid kit breakdown, plus the Build 42 first-aid guide at Supercraft Host (2026); the bite-is-fatal rule is unchanged in 42.20 and consistent across all sources. Exact bandage timers vary by wound and skill — confirm live in the Health Panel.