Food poisoning

Food poisoning is a type of sickness acquired by eating an old corpse. It is marked by the text FoodPois on the status line. It is eventually fatal if untreated, with the initial time-to-live is set to 10 + 1d9 turns.

Food poisoning is completely preventable (in NetHack) by avoiding eating old corpses. Corpses left by zombies and other undead (except wraith) are always considered old. A corpse is too old to eat after 6*(9+1d20) turns, where 6 is replaced with 8 if blessed and 4 if cursed.

Despite the name, food poisoning is unrelated to poison and is unaffected by poison resistance. Sickness resistance in vanilla Nethack is possessed only by ghouls and fungi.

Remedies

Food poisoning can be easily cured with any of the following:

• applying a non-cursed unicorn horn,
• praying to your god,
• quaffing a non-cursed potion of extra healing or full healing, a blessed potion of healing, or a potion of holy water (unless chaotic),
• casting a spell of cure sickness,
• eating a eucalyptus leaf,
• #invoking the Staff of Aesculapius.

The full list of less common remedies also includes:

• vomiting from eating tripe, a rotten egg, or in SporkHack, drinking a potion of salt water. This is quite unreliable, but it's there.
• polymorphing into a new version of yourself or a sickness-resistant monster. (A new version includes if you "fail" to change form, but get your attributes adjusted.)
• getting hit by a nurse's healing attack,
• sitting on a throne (1/13 chance).

And importantly, poison resistance is not a remedy; if you become food poisoned and rely on this you will die.

Messages

"Ulch - that <food type> was tainted!"

The corpse you are eating is tainted.

"You feel deathly sick."

You have contracted sickness and will soon die if untreated.

"It doesn't seem at all sickening, though..."

You would have contracted sickness but are resistant.

"You feel even worse."

"You feel much worse."

You have worsened your sickness, further shortening your time to live.

"You feel somewhat better."

Your have partially cured your sickness, lengthening your remaining time to live.

"What a relief!"

You have fully cured your sickness.

SLASH'EM

In SLASH'EM, you may also get food poisoning from swallowing a pill. You can cure food poisoning by sitting on a toilet. The Necromancer and the Undead Slayer roles start the game with innate sickness resistance.