# Potion of blood
The potion of blood is an item that appears in some variants of NetHack. They are primarily of interest to vampire players, and always appear as a blood-red potion when unidentified. Quaffing the potion breaks vegetarian conduct.[1]
In SLASH'EM, SlashTHEM and UnNetHack, potions of vampire blood can also be found, and are generally far more beneficial to player vampires as well - they have slightly different effects on non-vampires in each variant.
The potion of blood also appears in dNetHack, where it functions much differently compared to other variants.

Description

Potion of bloodPotion of vampire blood

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Name

blood

Appearance

blood-red

Base price

50 zm

Weight

20

Monster use

Will not be used by monsters.

Generation
Undead vampires, vampire lords and vampire mages have a 50% chance of generating with a potion of blood, with a (level)/30 chance that the potion will instead be vampire blood.[2] Potions of blood can be made via alchemy by dipping blood into potions of fruit juice.
In UnNetHack, you may very rarely generate a potion of blood by applying a horn of plenty.

Effects
The potion of blood is roughly equivalent to a potion of fruit juice for vampires - a player vampire that quaffs one will gain 30 nutrition for a blessed ptoion or 20 for an uncursed potion, with a diluted potion giving half of the appropriate value. The contents of a cursed potion of blood have congealed, and will give 0 nutrition. Non-vampire players that drink any potion of blood will instead become nauseous and vomit for 10d8 (more) turns.
Dipping a unicorn horn into a potion of blood will turn it into water, which is typically the only use for non-vampires. A thrown potion of blood that lands on a non-chaotic altar will convert the altar to chaotic, abuse your wisdom regardless of alignment and angers any attendant priest.[3]

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Name

vampire blood

Appearance

blood-red

Base price

350 zm

Weight

20

Monster use

Will not be used by monsters.

Generation
All players vampires that would normally start with food items will receive potions of vampire blood instead - they can also create a potion using the draw blood technique if they have a medical kit with usable phials and a level to spare. Undead vampires, vampire lords and vampire mages have a 50% chance of generating with a potion of blood, with a (level)/30 chance that the potion will instead be vampire blood.[2] Potions of vampire blood can be made via alchemy by dipping vampire blood into potions of fruit juice.
In UnNetHack, you may very rarely generate a potion of vampire blood by applying a horn of plenty, and you can get the effect of a potion of vampire blood if you quaff from sinks in&nbsp;UnNetHack.

Effects
Player vampires that drink a noncursed potion of vampire blood gain 800 nutrition points (400 if diluted). Additionally, a blessed potion increases your HP and max HP by the same amount as from a level gain. Non-player vampires (including fire vampires and star vampires) will drink the potion to heal themselves, restoring 2-10 HP if it is non-cursed and none if it is cursed.[4]
Non-vampire players that quaff the potion will instead be subjected to mostly-adverse effects that vary depending on the variant:

In SLASH'EM, a potion of any beatitude will polymorph you into a vampire, abusing your constitution; neutral characters will suffer a −3 alignment penalty, while lawful characters and Monks will suffer a −15 alignment penalty and anger their god.
In UnNetHack, the potion's beatitude determines the vampiric creature you polymorph into: a blessed potion will turn you into a vampire lord, an uncursed one polymorphs the player into a vampire as in SLASH'EM, and a cursed potion changes the player into a vampire bat.
Polymorphing induced by a potion of vampire blood is "semi-permanent" —you will revert back to your normal form if your HP is drained to zero, but there is no timeout for the form otherwise.
As with regular blood, dipping a unicorn horn into a potion of vampire blood will turn it into water. A thrown potion of vampire blood that lands on a non-chaotic altar will convert the altar to chaotic, abuses your wisdom regardless of alignment and angers any attendant priest.

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Strategy
Player vampires that encounter enemy vampires should kill them quickly to avoid losing any possible potions of vampire blood. Other players that are not chaotic and unwilling to risk their alignment or their god's wrath are better off converting the potions to water.

References

↑ source:SLASH'EM 0.0.7E7F2/potion.c#1040

↑ 2.0 2.1 source:SLASH'EM 0.0.7E7F2/makemon.c#1164

↑ source:SLASH'EM 0.0.7E7F2/dothrow.c#1830

↑ source:SLASH'EM 0.0.7E7F2/muse.c#963

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