Caustic Arrow

Borrowing a bit of toxic chemistry from the secretive Oriath Necromancers guild, a skilled archer infuses their arrowhead with a wicked venom. Once enchanted, the arrow will explode violently when it impacts a target, showering both foes and the surrounding area with a cloud of choking death. Anything living caught in the cloud will suffocate quickly, suffering heavy chaos damage until they move far away.

Description on the official Path of Exile website

Caustic Arrow is a bow attack that fires an arrow dealing chaos damage and exploding in a caustic cloud. Enemies standing within it receive a debuff that deals chaos damage over time. The caustic cloud does not poison and is therefore not affected by poison-related modifiers.

Skill functions and interactions

• Caustic Arrow will explode either at the targeted location or on the first monster or obstacle it hits.

• Multiple projectiles: additional projectiles added will cause additional caustic clouds, but debuffs from multiple clouds do not stack.

• Piercing: piercing Caustic Arrow projectiles will cause additional clouds each time they hit and will receive the chaos damage bonus any time they impact an enemy.

• Projectile damage: passive nodes and gems (such as ) that increase projectile damage will increase both the damage on hit and the area of effect damage.

• Concentrated Effect: decreases the size of the AoE and increase its damage. However, due to the nature of the skill and the wording of its modifiers, the damage increase will not appear on the tooltip.

• Point Blank: Point Blank does not affect the caustic cloud damage, it only affects projectile attack damage.

• Iron Grip: The strength bonus from the Iron Grip keystone passive does not affect the caustic cloud damage because the cloud is not considered an attack nor is it based on physical damage. The increased projectile damage portion of the will increase the cloud damage, but the strength bonus the support gem shares with the keystone will not apply.

• Accuracy: The projectile attack is subject to accuracy and can miss. However, the explosion will create a caustic cloud and do damage regardless of whether the projectile attack hit or missed. Piercing Caustic Arrow will not create additional clouds if missed.

• Duration: modifiers to duration will affect the duration of the caustic cloud.

• Culling strike: The increased damage from applies to cloud damage, but the cloud does not kill enemies instantly when they have less than 10% life.

• Curses: requires the target to be hit. The caustic cloud won't be affected by it. does affect the cloud.

Gem level progression

Level			Mana Cost	Damage Effectiveness	Attack Damage	Base Duration	Chaos Damage per sec	% of Physical Damage as Chaos	Exp.	Total Exp.
1	1	0	6	55%	55%	N/A	8.8	N/A	0	0
2	2	0	6	55%	55.5%	N/A	10.1	N/A	70	70
3	4	16	6	56%	56%	N/A	13.1	N/A	308	378
4	7	22	6	56%	56.5%	N/A	18.4	N/A	1554	1932
5	11	31	7	57%	57%	N/A	27.8	N/A	6667	8599
6	16	41	7	57%	57.5%	N/A	44	N/A	26047	34646
7	20	50	7	58%	58%	N/A	61.9	N/A	49725	84371
8	24	58	7	58%	58.5%	N/A	85.4	N/A	95714	180085
9	28	67	8	59%	59%	N/A	116.2	N/A	169595	349680
10	32	75	8	59%	59.5%	N/A	156.3	N/A	283759	633439
11	36	83	8	60%	59.9%	N/A	208.5	N/A	453996	1087435
12	40	92	8	60%	60.4%	N/A	275.9	N/A	703128	1790563
13	44	100	9	61%	60.9%	N/A	362.7	N/A	1061223	2851786
14	48	109	9	61%	61.4%	N/A	474.1	N/A	2065870	4917656
15	52	117	9	62%	61.9%	N/A	616.9	N/A	2507110	7424766
16	56	125	9	62%	62.4%	N/A	799.3	N/A	5798936	13223702
17	60	134	10	63%	62.9%	N/A	1031.8	N/A	15083919	28307621
18	64	142	10	63%	63.4%	N/A	1327.6	N/A	27792735	56100356
19	67	148	10	64%	63.9%	N/A	1600.8	N/A	43869739	99970095
20	70	155	10	64%	64.4%	N/A	1927.1	N/A	242081556	342051651
21	72	159	11	65%	64.9%	N/A	2179.2	N/A	N/A	N/A
22	74	N/A	11	65%	65.4%	N/A	2462.7	N/A	N/A	N/A
23	76	N/A	11	66%	65.9%	N/A	2781.5	N/A	N/A	N/A
24	78	N/A	11	66%	66.4%	N/A	3139.9	N/A	N/A	N/A
25	80	N/A	12	67%	66.9%	N/A	3542.6	N/A	N/A	N/A
26	82	N/A	12	67%	67.4%	N/A	3995	N/A	N/A	N/A
27	84	N/A	12	68%	67.9%	N/A	4503.1	N/A	N/A	N/A
28	86	N/A	12	68%	68.4%	N/A	5073.4	N/A	N/A	N/A
29	88	N/A	13	69%	68.9%	N/A	5713.4	N/A	N/A	N/A
30	90	N/A	13	69%	69.4%	N/A	6431.6	N/A	N/A	N/A
31	91	N/A	13	70%	69.8%	N/A	6822.8	N/A	N/A	N/A
32	92	N/A	13	70%	70.3%	N/A	7237.1	N/A	N/A	N/A
33	93	N/A	14	71%	70.8%	N/A	7675.8	N/A	N/A	N/A
34	94	N/A	14	71%	71.3%	N/A	8140.3	N/A	N/A	N/A
35	95	N/A	14	72%	71.8%	N/A	8632.2	N/A	N/A	N/A
36	96	N/A	14	72%	72.3%	N/A	9152.9	N/A	N/A	N/A
37	97	N/A	15	73%	72.8%	N/A	9704.1	N/A	N/A	N/A
38	98	N/A	15	73%	73.3%	N/A	10287.7	N/A	N/A	N/A
39	99	N/A	15	74%	73.8%	N/A	10905.4	N/A	N/A	N/A
40	100	N/A	15	74%	74.3%	N/A	11559.3	N/A	N/A	N/A

Alternate skill effect

Name	Cost	Description
Tentacle Caustic Arrow EffectTentacle Caustic Arrow EffectSkill Gem EffectYour Caustic Arrow becomes an area of ethereal purple tentacles.	120	Replaces the standard effect on a gem with an area of ethereal purple tentacles. Preview

Related helmet enchantments

The following helmet enchantments affect Caustic Arrow.

Note that helmet enchantments are no longer obtainable since version 3.23.0 and can only be obtained in permanent leagues as already enchanted items from before this patch.

Name		Labyrinth	Stats	Spawn Weighting
Enchantment Caustic Arrow Damage 1	66	Merciless Labyrinth	25% increased Caustic Arrow Damage	helmet 75
Enchantment Caustic Arrow Damage 2	75	Eternal Labyrinth	40% increased Caustic Arrow Damage	helmet 75
Enchantment Caustic Arrow Duration 1	66	Merciless Labyrinth	20% increased Caustic Arrow Duration	helmet 75
Enchantment Caustic Arrow Duration 2	75	Eternal Labyrinth	30% increased Caustic Arrow Duration	helmet 75
Enchantment Caustic Arrow Area Of Effect 1	66	Merciless Labyrinth	16% increased Caustic Arrow Area of Effect	helmet 75
Enchantment Caustic Arrow Area Of Effect 2	75	Eternal Labyrinth	24% increased Caustic Arrow Area of Effect	helmet 75
Enchantment Caustic Arrow Wither On Hit 1	66	Merciless Labyrinth	Caustic Arrow has 14% chance to inflict Withered on Hit for 2 seconds base Duration	helmet 75
Enchantment Caustic Arrow Wither On Hit 2	75	Eternal Labyrinth	Caustic Arrow has 20% chance to inflict Withered on Hit for 2 seconds base Duration	helmet 75

Version history

Version	Changes
2.1.0	Poison Arrow has been renamed to Caustic Arrow as part of the poison changes. The damage of this skill has been increased by around 37% at level 1, but reduced by around 42% by level 20. This reduction is more than compensated for by supporting the skill with the new supports. Caustic Arrow's mana costs have been increased, from 5 to 8 at level one, and from 13 to 16 at level 20.
2.0.0	Reduced the mana cost across all levels. Now grants 0.5% increased area of effect radius per 1% of quality (was 1% per 1% quality). Damage increased by approximately 26% at gem level 20.
1.3.0	Poison Arrow can now damage totems.
1.1.2	Damage has been increased by 8% at level 1, scaling up to an increase of 75% at level 15 of the gem.
1.0.6	Poison Arrow's damage has been increased at higher levels. It now does roughly 35% more damage at gem level 15.
1.0.3	Damage progression has been increased. It is now around 15% better at level 15 than it was in 1.0.2.
1.0.2	Early levels of Poison Arrow have had their damage reduced by around 35%.
0.9.13	It now starts off around 85% stronger at level 1 and is about 1% weaker at level 15.
0.9.12	Rebalanced its mana cost progression to reflect the fact that it does damage in a comparable way to Spells.
0.9.9	The size of the Poison Arrow clouds now scale with their Area of Effect radius properly.
0.9.7	Improved the effects of Poison Arrow.
0.9.5g	Fixed a bug where the Poison Arrow cloud would appear where you clicked even if the arrow was stopped before then by a wall.
0.9.5	Fixed Poison Arrow so that damage from the degeneration is scaled properly for PvP.
0.9.4	Increased the damage.
0.9.2	Poison Arrow does more damage at higher levels than before.
0.8.7	Poison Arrow does additional chaos damage on the actual arrow itself now, in addition to the cloud damage.
0.8.5	Added new skill prototype: "Poison Arrow" (Fires an arrow which explodes in a cloud of poison. Enemies who enter the cloud are poisoned for a short time, taking chaos damage)