Illness in Project Zomboid (not the zombie virus)

The Sick moodle is a single meter fed by several sources: food sickness, sickness from decaying corpses, and the Knox infection. The icon shows whichever source is highest, and it never tells you which one that is. That is why a Queasy icon on its own proves nothing.

The carry penalties (1, 2 and 3 points at Nauseous, Sick and Fever) come from (one source). Several sources agree that only the Fever stage actually drains health. The common cold is separate: it has its own Has a Cold moodle and does not push the Sick meter toward Fever. See moodles for every other icon and health for the Health panel.

A cold comes from being wet and chilled. The Wet moodle runs Moist, Wet, Soaking and Drenched; at Soaking the game warns you could catch a cold, and at Drenched it says you will. Low body temperature (the Hypothermia moodle) raises the risk too, and sources say being exhausted makes it worse.

The Has a Cold moodle has four stages: Runny Nose, The Sniffles, Head Cold and Nasty Cold. Early stages bring the odd sneeze. From Head Cold on you sneeze and cough, and the game describes you as feeling sick and slow.

Sneezing and coughing make noise that can give you away near zombies. Players report that holding a tissue or toilet paper muffles it (one source).

Cure: get indoors, change out of wet clothes or dry off with a towel, warm up by a fire or in thicker layers, and sleep. Severity falls during sleep and a cold usually clears within a few in-game days. Common Mallow, found by foraging, lowers cold strength directly. Colds are rarely dangerous by themselves, but cold weather that caused one can kill through hypothermia; see winter survival and clothing.

Food sickness builds when you eat or drink something bad: rotten food, raw or undercooked meat, poisonous wild mushrooms or berries, and unboiled rain or river water. Lighting a cigarette as a non-smoker also adds a chunk of food sickness, per one Build 42 source; see smoking.

• Check freshness before eating. Rotten food is marked as such in its tooltip.
• Cook meat and fish fully. See cooking.
• Boil or purify water from rain barrels, rivers and lakes. See water.
• Learn which wild plants are safe before eating them.

The sandbox has an Enable Poisoning option (on by default). We could not confirm the details of bleach poisoning in Build 42, so treat any food a stranger hands you in multiplayer with care.

Cure: stop eating the bad item first. Food sickness then fades on its own as long as nothing keeps feeding it. Staying Well Fed and rested speeds things up. Lemongrass removes about 12 points of sickness per use and then has a cooldown; Ginger Root removes about 1 (one source). Weak Stomach and Iron Gut change how much bad food hurts you; see traits.

Piles of rotting bodies make you sick. The Noxious Smell moodle warns you first (Bad Smell, Awful Odor, Overwhelming Stench), and flies are a visual hint. The sickness lands on the same meter as food poisoning.

Sources disagree on how many bodies it takes. Two Build 42 sources say the effect starts above 5 corpses, with one adding that the count stops mattering beyond 25. An older source quotes more than 20 bodies. Bodies are counted on your floor only, and indoor and outdoor corpses are counted separately, so going upstairs or stepping outside a building full of bodies can help.

Rates are (one source). A gas mask, respirator or NBC mask with a working filter blocks the effect; cloth masks and bandanas help a little. Filters drain while they work. The lasting fix is removing bodies: drag, burn or bury them away from base. See corpses for disposal methods.

Work through the causes in order:

1. Sneezing, coughing, Has a Cold icon? That is a cold. It uses a different moodle from Queasy.
2. Ate something risky, or near a pile of bodies? Remove the cause, eat well, rest, and watch the Sick meter. If it starts falling within a day or so, it was food or corpse sickness.
3. Any zombie wound in the last few days? Check the Health panel for bites, scratches and lacerations. If Sickness keeps climbing after every other cause is gone, assume Knox.

A red "Infected" label on a wound in the Health panel means an ordinary dirty-wound infection, not the zombie virus. Treat it with disinfectant, clean bandages and antibiotics; see first aid and medicines.

Opinion If you were wounded by a zombie and feel Queasy, plan as if infected until a full day passes with the meter dropping. Writing a note to yourself about when each wound happened makes the call much easier.

For sandbox options that control corpse sickness and poisoning, see sandbox settings.