Potion of sickness

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! Pink potion.png
Name sickness
Appearance random
Base price 50 zm
Weight 20
Monster use Will not be used by monsters.

A potion of sickness is a type of potion that appears in NetHack. As indicated by some of the messages associated with it, the potion is biologically contaminated fruit juice, and those messages use the name of that fruit when printed.


Rogues start the game with an uncursed potion of sickness.[1]

Pestilence will always generate with a stack of several potions of sickness.[2]

Applying a charged horn of plenty has a 0.3% chance of generating a potion of sickness.[3][4]


When performing alchemy by mixing two random types of potion that have no recipe, and the dipped stack of potions is not diluted, the result is a stack of potions of sickness 22.5% of the time.[5] Dipping a stack of fruit juice potions into a potion of sickness will 'contaminate' the stack, turning them into potions of sickness. Dipping a potion(s) of healing, extra healing, or full healing into a potion of sickness will clear the contamination and turn them into potions of fruit juice.


Quaffing a potion of sickness will cause you to lose HP, lower one of your attributes and possibly abuse constitution, depending on beatitude and whether or not you have poison resistance[6] - it does not cause terminal sickness (e.g. as with food poisoning). Quaffing the potion will also shock you out of hallucination and back to your senses.[7]

The effects of beatitude on the potion are displayed below:

Case You have no poison resistance You have poison resistance
blessed You lose 1 hit point. You lose 1 hit point.
uncursed You lose 1-10 hit points, one of your attributes is reduced by 3-6, abuse constitution. You lose 1 hit point, one of your attributes is reduced by 1, abuse constitution.
cursed You lose 1-15 hit points, one of your attributes is reduced by 3-6, abuse constitution. You lose 1 hit point, one of your attributes is reduced by 1, abuse constitution.

If you are a Healer, you are completely protected from these effects;[8][9] if you have the sustain ability property, your attributes are not reduced.[10]

While monsters do not quaff or otherwise use potions of sickness, Pestilence will quaff potions of sickness to heal himself like other monsters would with a potion of healing; hitting Pestilence with the potion will have the same effect.[11] Inhaling the vapors of a thrown, boiled or smashed potion causes you to lose 5 HP regardless of beatitude or poison resistance, or else sets your HP to 1 if you currently have less than 5, and abuses constitution; if you are a Healer, the vapors have no effect.[12]


If you #dip a unicorn horn into the potion, it will become a potion of fruit juice - this also happens if you cancel the potion.

If you dip darts, arrows, shuriken, or crossbow bolts into a potion of sickness, it will coat the stack of projectiles in poison, using up the potion and prompting you to type-name it if unidentified. Poisoned weapons do d6 extra damage and have a 110 chance of instantly killing non-resistant monsters;[13] the poison has a 110 chance of wearing off on each successful attack.[14]

Throwing and wielding

Hitting a monster with a wielded or thrown potion will reduce their hit points if successful: monsters with a sickness attack or poison resistance are immune, while other monsters have their current HP and maximum HP halved, each subject to separate rolls versus monster MR. if the monster's maximum HP is brought below the current HP, the current HP is reduced to the new maximum HP.

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

As of commit 43f42b35, the effect of hitting a monster with a potion of sickness no longer depends on monster MR, but halves only the current monster HP of non-poison-resistant monsters, not the maximum HP.


Potions of sickness are typically best used for poisoning projectiles, though lawful characters will take a -1 hit to their alignment record for each use of a poisoned weapon; alchemy makes it somewhat easy to procure more potions for poisoning projectiles with. There are many late-game monsters, up to and including some otherwise-powerful quest nemeses, that lack poison resistance and can be easily felled by something as simple as a stack of poisoned projectiles; Tourists in particular that hold on to their starting stack of +2 darts can poison them to use as an effective weapon against the Master of Thieves.

While a potion of sickness can be used as a hallucination cure if you can mitigate the HP and attribute loss (e.g. with poison resistance, a potion of restore ability, or a ring of sustain ability), they are only worth using for this purpose if you lack any other cure, such as potions of extra healing, full healing or a unicorn horn.

For players that have no interest in poisoned weapons, this potion is a good candidate for dilution or else converting to fruit juice for other purposes.


The potion of sickness is one of four 50zm potions, along with the potions of fruit juice, see invisible and booze - incidentally, all of the other potions can be made from fruit juice.

Potions of sickness can be easily identified by dip-testing with a unicorn horn, as discussed above; while cancelling them also turns them into fruit juice, cancelling the potion of see invisible has the same effect. Dipping a non-poisoned missile weapon into a potion of sickness will form a coating on it, which is reliable for informal identification.


The potion of sickness first appears in Hack for PDP-11, a variant of Jay Fenlason's Hack; Hack 1.21, another variant, has a somewhat-similar potion of poison.

In versions prior to NetHack 3.6.3, the case for dipping healing potions fell through to the unicorn horn case due to a missing break statement, causing the combination of healing and sickness to alchemize to fruit juice, and the combination of healing and hallucination, blindness, or confusion to alchemize to water.[15][16] This behavior was made explicit and intentional in NetHack 3.6.3 via commit c6b75407.


Yecch! This stuff tastes like poison.
You quaffed a potion of sickness.
(But in fact it was mildly stale <slime mold> juice.)
This line is added if the potion was blessed.
(But in fact it was biologically contaminated <slime mold> juice.)
This line is added if you quaffed a non-blessed potion and have poison resistance; you only lose one attribute point.
Fortunately, you have been immunized.
You are a Healer, so you suffer no ill effects.
You are shocked back to your senses!
You were hallucinating, and were cured by quaffing the potion.
You feel weaker.
Your strength was lowered.
Your muscles won't obey you.
Your dexterity was lowered.
You feel very sick.
Your constitution was lowered.
Your brain is on fire.
Your intelligence was lowered.
Your judgement is impaired.
Your wisdom was lowered.
You break out in hives.
Your charisma was lowered.
<monster> looks rather ill.
A monster without immunity was hit by a potion of sickness, or Pestilence was hit by a potion of healing.
<monster> looks unharmed.
A monster with a sickness attack or poison resistance was hit by a potion of sickness.
<potion> forms a coating on <item>.
You dipped a poisonable item into a potion of sickness.



In SLASH'EM, bladed weapons can be poisoned as well using a potion of sickness, and poisoned weapons are also subject to a weight-based chance of losing their poisonous coating (1 in [10 - (weight/10)] chance).

The Chamber of Junk in the Lawful Quest has a 25 chance of containing two cursed potions of sickness.


EvilHack also allows bladed weapons to be poisoned using a potion of sickness.


  1. src/u_init.c in NetHack 3.6.7, line 127
  2. src/makemon.c in NetHack 3.6.7, line 1312
  3. src/mkobj.c in NetHack 3.6.7, line 2212: The code chooses a random potion, discarding magical potions. Potions of sickness will be kept if initially chosen, but if a magical potion is initially chosen, potions of sickness will be rejected as replacements - see the next reference for details.
  4. src/objects.c in NetHack 3.6.7, line 813: rnd_class(POT_BOOZE, POT_WATER) chooses the non-magical potions, but the loop around this rejects potions of sickness.
  5. src/potion.c in NetHack 3.6.7, line 2058: Potions have a 110 chance of blowing up before this point. The remaining 910 of the time, 28 of random alchemy results from non-diluted potions become potions of sickness.
  6. src/potion.c in NetHack 3.6.7, line 855
  7. src/potion.c in NetHack 3.6.7, line 897
  8. src/potion.c in NetHack 3.6.7, line 859
  9. src/potion.c in NetHack 3.6.7, line 867
  10. src/potion.c in NetHack 3.6.7, line 877
  11. src/potion.c in NetHack 3.6.7, line 1444
  12. src/potion.c in NetHack 3.6.7, line 1680
  13. src/uhitm.c in NetHack 3.6.7, line 1137
  14. src/uhitm.c in NetHack 3.6.7, line 1129
  15. src/potion.c in NetHack 3.6.2, line 1766: Note the lack of breaks in the cases down to the unicorn horn case
  16. src/potion.c in NetHack 3.6.3, line 1795: Newly added fall-throughs are marked via comments