There are several types of poisons in ZDoom.
Attacks from monsters or weapons can cause poison damage. Such damage is not inflicted in one go, but drain the victim's health over a period of time. Standard poison damage, as used in Hexen (serpent staff, poison cloud) only affects the player, and monsters are instead hurt by normal damage from these attacks; however it is possible in ZDoom to create poison damage that affects monsters in the same way as players, with the PoisonDamage property on a projectile or puff. The flags ADDITIVEPOISONDAMAGE and ADDITIVEPOISONDURATION can also be used. While poisoned, a player's screen is affected by a greenish palette flash, the intensity of which depends on the severity of the poison.
Certain sector types originating from Strife can also cause poisoning. Instead of regularly inflicting damage while the player is inside as others damaging floors do, sector types 105 and 116 increase a player's "hazard counter", by two or four points respectively, for every tic that player remains in the poisoning sector. This hazard counter is itself decreased by one point every tic until it reaches zero (so, while a player remains in a poison sector, the counter actually increases by one or three points). Once the hazard count reaches 560 (after 16 seconds of accumulation in type 105, or 5 seconds and 12 tics in type 116), the player is inflicted five points of slime damage every 32 tics. This damage will persist as long as the hazard count remains above 560, so a severely poisoned player can suffer from damage even after exiting the poisoning sector. Protective items such as the RadSuit or EnvironmentalSuit protect against this poisoning effect. While poisoned, a player's screen is affected by a greenish palette flash using the same color as the Doom RadSuit blending.
Strife also features a crossbow that shoots poisoned bolts. This does not correspond to an actual poison as far as the game system is concerned; instead the PoisonBolt instantly kills any non-boss enemy with blood. Enemies with the NOBLOOD flag are entirely immune, and enemies with the BOSS flag (but not NOBLOOD) are merely inflicted 50 points of normal damage.
- ADDITIVEPOISONDAMAGE and ADDITIVEPOISONDURATION flags
- ArtiPoisonBag and specifically ArtiPoisonBag1
- CWeapStaff and CStaffMissile
- Damage types and custom damage types
- PoisonBolt, PoisonBolts and StrifeCrossbow2
- PoisonDamage and PoisonDamageType properties
- PowerIronFeet and PowerMask