Does the Gem of Efficacious Toxin's debuff stack?
If multiple party members have a Gem of Efficacious Toxin at rank 25+, will the "All enemies you poison take 10% increased damage from all sources" debuff stack? So when multiple people apply the DOT, do you see 10% damage increase or more?
Best Answer
My research indicates that you will see only a 10% damage increase.
According to Wikia, a mob can only have one of this gem's '10% increased damage taken' debuffs at a time, irrespective of how many players are applying it:
At rank 25, it also increases damage the poisoned target takes from all sources (including other players), making this gem useful to classes focusing on elements other than Poison. If [t]his debuff is applied by more than one player, it will not stack.
This would appear to be backed up by a discussion on the US Battle.net forums:
are you referring to if all four in party uses the gem and have it at least 25%? then no, the 10% doesn't stack. mobs won't take 40%~ additional damage.
Pictures about "Does the Gem of Efficacious Toxin's debuff stack?"



How good is gem of efficacious toxin?
Gem of Efficacious Toxin is +10% damage & -10% damage by enemies. The rank based poison damage will eventually become irrelevant, except for speed runs. Bane of the Stricken at rank=150 is +2.3% damage. So takes at least 5 stacks for that to match GoET.Does gem of efficacious toxin Proc essence of anguish?
The Gem of Efficacious Toxin makes your hits poison the enemies then they take 10% increased damage from poison and deal 10% less damage. The Essence of Anguish When you deal poison damage to an enemy, they receive 50% increased poison damage from all sources for 10 seconds.Diablo 3 RoS 2.1 : Gem of Efficacious Toxin Explained by Maximus Grahamicus
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Uzunov Rostislav, Jonny Lew, Karolina Grabowska, Karolina Grabowska
