Open Wounds

% Chance of Open Wounds can cause target to bleed uncontrollably when applied with a successful weapon attack, draining life and stopping any unit damage regeneration for its 8 second (200 frame) duration. Bleeding occurs even when life drain cannot be applied to target.
% Chance from multiple sources is summed, although when two weapons are equipped only that of the attacking weapon is added (that of the other weapon is ignored). >100% is redundant.
Applied by any melee or ranged attack with the exception of Blade Sentinel, Blade Shield and the additional arrows of Multiple Shot (only applied by the original two arrows).
Always applied to another player, but only applied to other units (monster, hireling or pet) if their life value changes, either due to damage taken or regenerated. If no damage is taken then OW won't be applied if regeneration has already been stopped by Prevent Monster Heal.
Life drain is dependent on the level of the player, hireling or Iron Golem applying it. Life drain per frame in bits (1 bit = 1/256 point) is currently calculated as follows:

Stat	Level
Stat	1-15	16-30	31-45	46-60	>60
Bit Life Drain/Frame	(9*lvl)+31	(18*lvl)-104	(27*lvl)-374	(36*lvl)-779	(45*lvl)-1319

[1] [2]

Life drain per frame in bits may then be modified depending on the attack used and the target, and rounded down to the nearest bit:

Target	Current Life
Target	Melee	Ranged
Special Unit	/2	/2
Player	/4	/4

[3]

Special units are monsters other than normal and minion monsters (Champion, Unique, Super Unique, boss (excluding normal and minion Putrid Defilers) and Prime Evil). Life drain is unmodified against all other targets.
Although duration is 8 seconds (200 frames), life drain is not applied in the first frame and so points of life drain are calculated as follows:

Life Drain	Multiplier
Points/Second	*25/256
Total Points	*199/256

Life drain cannot be countered by any form of damage reduction.
Duration cannot be reduced by Cleansing or Fade. [4] [5]
When OW is applied again before the previous duration expires, duration simply gets reset regardless of the level of the second application: if OW is applied at level 80 while it is still being applied at level 60, level 60 damage is still applied for the reset duration (and vice versa).
Poison damage and length can be applied separately and simultaneously. [6]
Replenish Life and + Life After Each (Demon) Kill from items, and healing from potions, Prayer (including its passive bonuses to Cleansing and Meditation) and Holy Bolt still apply while active.
Replenish Life from items is a direct counter: OW applied by a level 30 player's melee attack on another player would result in 109 bit life drain per frame, which Replenish Life +109 would counter entirely; a ranged attack would result in 54 bit life drain per frame, which Replenish Life +54 would counter entirely.

Pelt

Template:D2 Skill bonus |- |33% !align=left|Cerebus' Bite Blood Spirit |71 !Yes |}

Body armor

Template:D2 Skill bonus |- |25% !align=left|Boneflesh Plate Mail |35||No |- |33% |align=left|Duress body armor |47||No |- |35% !align=left|Crow Caw Tigulated Mail |45||No |- |40% !align=left|Toothrow Sharktooth Armor |56||No |}

Weapon

Template:D2 Skill bonus |- |25% |align=left|Um Rune in weapon socket |47||No |}

Melee weapon

Template:D2 Skill bonus |- |66% |align=left|Fury melee weapon |65||No |- |100% |align=left|Malice melee weapon |15||No |}

Missile weapon

Template:D2 Skill bonus |- |30% !align=left|Riphook Razor Bow |39||No |- |33% !align=left|Langer Briser Arbalest |40||No |- |33% !align=left|Gut Siphon Demon Crossbow |79||No |}

Axe

Template:D2 Skill bonus |- |15% !align=left|Skull Splitter Military Pick |28||No |- |25% |align=left|Crescent Moon axe |47||No |- |25% !align=left|Butcher's Pupil Cleaver |47||No |- |25% |align=left|Beast axe |63||No |- |25% |align=left|Doom axe |67||No |- |33% !align=left|The Scalper Francisca |65||No |- |33% !align=left|Lacerator Winged Axe |76||No |- |50% !align=left|The Gnasher Hand Axe |7||No |- |50% |align=left|Steel axe |13||No |- |50% |align=left|Kingslayer axe |53||No |- |50% !align=left|Razor's Edge Tomahawk |75||No |- |60% !align=left|Goreshovel Broad Axe |19||No |}

Claw

Template:D2 Skill bonus |- |25% |align=left|Chaos claw |57||No |}

Club

Template:D2 Skill bonus |- |25% !align=left|Fleshrender Barbed Club |46||No |}

Dagger

Template:D2 Skill bonus |- |50% !align=left|Fleshripper Fanged Knife |76||No |}

Hammer

Template:D2 Skill bonus |- |25% |align=left|Beast hammer |63||No |- |25% |align=left|Doom hammer |67||No |}

Mace

Template:D2 Skill bonus |- |25% !align=left|Bloodrise Morning Star |20||No |- |50% |align=left|Steel mace |13||No |}

Polearm

Template:D2 Skill bonus |- |25% |align=left|Crescent Moon polearm |47||No |- |25% |align=left|Doom polearm |67||No |- |30% !align=left|Soul Harvest Scythe |26||No |- |50% !align=left|Woestave Halberd |38||No |- |50% !align=left|The Meat Scraper Lochaber Axe |49||No |}

Scepter

Template:D2 Skill bonus |- |25% |align=left|Beast scepter |63||No |}

Spear

Template:D2 Skill bonus |- |35% !align=left|Bloodthief Brandistock |23||No |- |40% !align=left|The Impaler War Spear |39||No |}

Sword

Template:D2 Skill bonus |- |25% |align=left|Crescent Moon sword |47||No |- |33% !align=left|Blood Crescent Scimitar |10||No |- |50% |align=left|Steel sword |13||No |- |50% |align=left|Kingslayer sword |53||No |- |50% !align=left|Bloodmoon Elegant Blade |69||No |- |80% !align=left|Ripsaw Flamberge |35||No |}

Throwing weapon

Template:D2 Skill bonus |- |33% !align=left|The Scalper Francisca |65||No |- |33% !align=left|Lacerator Winged Axe |76||No |}

Shield

Template:D2 Skill bonus |- |50% !align=left|Swordback Hold Spiked Shield |20||No |}

Belt

Template:D2 Skill bonus |- |(5-10)% !align=left|Blood belt |13||No |}

Reference

Special Magic Effects (Arreat Summit)
Open Wounds (Technical Discussion)
Nefarius, Open Wounds Explained (v1.11b) (Phrozen Keep)