Sickness

Sickness is a terminal status affliction that, if untreated, will cause instadeath after a few turns.

The game uses "deathly sick" to specifically herald this condition, whereas there are many other cases where you simply "feel sick". Also note that sickness is not caused by a potion of sickness but is cured by a spell of cure sickness, among other things.

Sickness resistance in vanilla NetHack is possessed only by ghouls and fungi, which happily feast on old corpses.

Types of sickness

There are two distinct types of sickness, indicated separately on the status line. You can also suffer both conditions simultaneously. The effects and remedies are identical, except that only food poisoning can be cured by vomiting.

Food poisoning

Food poisoning is acquired by eating an old corpse. It is marked by the text FoodPois on the status line. The initial time-to-live is set to 10 + 1d9 turns.

Despite the name, food poisoning is unrelated to poison and is unaffected by poison resistance.

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.

Illness

Illness is conferred by the disease attacks of certain monsters, listed below. It is marked by the text Ill on the status line.

• & Demogorgon
• & Juiblex
• s Scorpius
• & Pestilence
• w rot worms (SLASH'EM)
• a locusts (SporkHack)
• F gray fungi (SporkHack)

The first time you contract the illness, a turns-to-live timer is started, set to between 20 and (19+Con). Each additional illness attack while you are Ill divides the remaining turns-to-live by roughly 3.

Remedies

Sickness 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 (unless chaotic) a potion of holy water
• 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 cures food poisoning only, not illness. 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 old enough to cause food poisoning.

"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 ("much" if reduced by at least half).

"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.

Enlightenment may reveal any of the following, which are self-explanatory:

"You are sick from food poisoning."

"You are sick from illness."

"You are immune to sickness."

SLASH'EM

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