Left 4 Dead Wiki

"Puke in the hole!"
"Here comes the Bile, you sons of bitches!"

The Bile Bomb (a.k.a. Boomer Bile, Vomit jar or simply puke) is a weapon which appears in Left 4 Dead 2. The weapon was first mentioned in the achievement list. The Bile bomb is a throwable glass jar containing green Boomer bile. When thrown, it sends the Infected horde to wherever it hits, acting as a bait for 20 seconds, and potentially causing "friendly-fire" by leading the Horde to attack any Infected coated in the bile. When a Bile bomb hits any type of Infected, Survivors will be able to see the affected Infected's aura outlined in bright purple. Bile bombs, overall, allow for a brief moment of rest and preparation during a battle.

The Bile bomb can often be found in the first two levels of Dead Center. It may also be dropped by CEDA Worker Infected, though this is less common. The Bile bomb uses the same inventory slot as the Pipe Bomb and the Molotov Cocktail, so only one of the three can be carried at one time.

The bomb spreads Boomer bile on whatever it hits, and the Horde summoned by the Survivors will attack whatever is covered in bile, including other Infected. If the Bile bomb is used on an empty space, it will summon a Horde and all of the local Infected to the place where the bomb landed. Usually, the Director will spawn a Horde if there are not a lot of Infected, and the Common or Uncommon Infected will mostly ignore the Survivors so long as the bile is still in effect and they are not in the way, making them easy targets. The Common Infected hit by the bomb will begin attacking each other, as well.

The bomb can also help in Tank fights as it calls a Horde to attack it. The effect of this is only marginal, however, and usually just serves to slow the Tank down and damage it slightly rather than kill it. Sometimes, though, the Tank will be rendered immobile by the Common Infected hitting it. This can buy the Survivors a lot of valuable time―however, Survivors must be careful, as some of the Common Infected might survive and attack the Survivors, making this tactic especially dangerous on Expert and Realism unless multiple Bile Bombs happen to be lying around such as the Burger Tank restaurant during Hard Rain. If the Tank is AI-controlled and bile is applied to other Infected, the Tank will ignore the Survivors and instead focus on attacking the Infected covered in bile, which can also buy the Survivors some time and cut down on the threat of other Infected attacking with the Tank.

The bomb can also be used to confuse Special Infected as it will make any two of them that have been hit to fight one another as well as the oncoming Common Infected. Throwing the Bile bomb on a Survivor will not draw a Horde to attack; however, the Horde will be drawn to the location where the bomb impacted, and will attack any Survivors within that impact area.

Unlike the Pipe Bomb, the Bile bomb should not be used to lure Common Infected away from Survivors soaked in Boomer bile, as it will not do anything unless the Bile bomb hits any Infected; the AI Infected prioritizes Boomer bile-soaked Survivors over that of the Bile bomb.

Official Description[]

Give the infected a taste of their own medicine with this CEDA-developed gastrointestinal projectile. Any zombie you soak with this puke grenade will be swarmed by common infected.[1]


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Bile bomb used on a Tank.

  • Even though the Bile bomb is designed to make Infected attack each other, it can also be used as a distraction. Use it during Crescendo Events or finales to reach the escape vehicle to make the Special Infected the only threat when one is thrown. However, this means that you must manually kill the infected, which a Pipe Bomb does on its own.
    • It can also be used for speed-runs through a chapter in the following ways:
      • By throwing the bile inside the safe room then closing the door, the ensuing Common Infected will attempt to attack the safe room door to destroy it. As safe room doors can only be destroyed by a Tank (which is not lured by them), they will be stuck attacking the door. This results in little to no Common Infected as the current Commons are busy attacking the safe room door.
      • You can throw it off an area the team will most likely not visit and run through the hordes of Infected as they surge to that spot. Make sure everyone is ready to go before you do so.
      • Players should be wary of Special Infected spawning as they are not affected by the bile like Common Infected, especially for Tanks when doing a speed-run as it can create an unexpected and sudden fight.
  • When thrown at Special Infected, it will result in both of them fighting each other. This is rather rare as they are usually not bunched together and spawn in various areas to attack the Survivors from.
  • Be wary of using Bile bombs during "Hard Rain", as it will spawn Worker Infected. Unless other Common Infected are hit by the bomb, they will ignore its effects and head straight for the Survivors instead, which can be dangerous on Expert and Realism modes.
  • A Bile bomb should be used on a horde only if you anticipate one coming or the team is in critical condition.
  • Bile bombs are very rare to find during "Dark Carnival" and "The Parish". In "Dark Carnival", they only appear during "The Highway" and "The Concert" (one always spawns in this chapter), and for the latter during "The Park" and "The Quarter". Teams should have one player carry a Bile bomb to be used during Crescendo Events or finales.
    • Note that in "No Mercy" the only way to obtain a bile bomb is to kill the CEDA Worker Infected that spawns near the end of "The Sewer" and "the hospital", since the bile bomb does not have a chance show up in the entire campaign.
  • Bile bombs are much more effective in Versus than in Campaign Mode. As the Special Infected are now controlled by players, hitting them with a Bile bomb blinds them temporarily and allows the horde to attack and slow them down. This works well on Tank players who will struggle to get the Common Infected out of the way unless aided by a tactical Boomer.
  • They are useful on "The Hotel" and "The Bridge", as Common Infected will still chase after them and fall to their deaths, allowing the players to progress with ease.
  • With practice, players can kill or make Witches retreat if a Bile bomb is thrown from a long distance. When used against the Tank, it will not trigger the fight and will deplete most if not all of his health, making the fight against him easier.
  • Do not block incoming Infected as they run towards the impact zone. This will result in them stopping and attacking you because you are blocking their way, similar to blocking a Witch when she is chasing after the startler or retreating.
  • When facing a startled Witch, do not use Bile bombs against her. She will be too fast for the Horde to catch up, decimate them with ease and result in her targeting the thrower if hit by one. It does not slow her speed down either so use a Molotov instead for this purpose.
  • If one manages to throw a Bile bomb and then throw a Molotov where the Bile Bomb lands, the infected will walk right in the fire, saving the needed ammo to kill them. However, it's a lot more effective to use just a Pipe Bomb or a Grenade Launcher.
  • The Bile bomb becomes more dangerous to use the higher the difficulty is. As hordes become stronger in Advanced and Expert, be wary of when to throw it: it can lead to the team being inconvenienced since it will spawn a horde even if there isn't one.
    • This is especially important against Tanks - if the team is already taking a while to kill the Tank, tossing a Bile bomb to coat the Tank may just lead to the Survivors needing to fight an angry, damaging horde and the Tank once its effect expires.
  • The Bile bomb is a mix of both the Pipe bomb and Molotov. It has the area effect of the Molotov while using the attention grabbing mechanics of the Pipe bomb.
    • This can be used with explosive or incendiary items to kill all the Infected in one go.


Main article: Achievements

Septic tank
Use a bile bomb on a Tank.

Robbed zombie
Collect 10 vials of Boomer vomit from Infected CEDA agents you have killed.


  • The concept for the Bile bomb was mentioned by a user on the official Steam forums.[2] Credit for the weapon, however, has not been assigned, as there has been no proof that one single fan came up with the idea, or if Valve coincidentally created it.
  • The Boomer's vomit is a dark green liquid, but the Bile bomb's is a lighter color. This could be because CEDA refined the bile for research purposes, possibly reducing its power to lure Infected in the process, as Common Infected are more attracted to Boomer vomit over a Bile bomb.
    • Another explanation is that human pheromones or tissue was added to "activate" the bile. Since bile from a Boomer does not summon Infected unless it hits a Survivor, it may be activated by human pheromones or tissue. Use of stale samples of these pheromones or tissues may be the cause for the infected's preference for bile-soaked Survivors over Bile bombs.
  • The bile from the Bile bomb will only cover Infected, while the bile from the Boomer will only cover Survivors.
    • It also appears to have originally affected Survivors near the blast radius, according to a game instructor line stating, "A Survivor bile-bombed you"―however, this line is used when hit with bile as an Infected in Versus. There were also, according to captions in the game files, lines stating that Boomer bile attracts the horde, and that you shouldn't throw it on them. It was removed due to the possibility of griefing, but altering the values of the console commands vomitjar_radius_survivors and vomitjar_duration_survivors will replicate its original behavior. You'd still need to turn on sv_cheats of course.
  • The Bile bomb may have indicated that the military was trying to research and create an effective bioweapon against the Infected. Or perhaps, simply, it was a result of efforts to find out the effects and extent of mutations from the virus. However, CEDA infected will also drop it whereas no militant has been observed to possess one in the first place.
  • It seems that CEDA may have come up with the names for the Infected, or at least the Boomer, since the label clearly states "Boomer" Excretion. It is also possible that they used the name the Survivors gave it, so that they knew what was in the bottle.
  • The achievement "Robbed Zombie" is a reference to movie director and rock artist "Rob Zombie".
  • The Bile Bomb label says "Sample 0841", which means that CEDA has been collecting samples for some time.
  • It is notably strange how Survivors in "Swamp Fever" can find Bile bombs, because the Village En Marais ignores help from CEDA, and the bile bomb is an improvised weapon as a result of CEDA research. However, these jars may have been carried there by other Survivors or scavenged from the inhabitants of the village.
  • Strangely, the Worker Infected is immune to the effect of the Bile Bomb and will attack the Survivors rather than chase the bomb. The Worker Infected wears nothing to show a resistance or immunity to this like he does for pipe bombs (he wears earmuffs, therefore, he can't hear it beeping).
    • The bile bomb shares the pipe bomb's programming when it comes to attracting the Infected. Since the Worker Infected is immune to the attraction of pipe bombs, he is also immune to the attraction of bile bombs, therefore making him not chasing it even though his senses picked them up. He will chase if it hits other infected though (like a Tank)
  • It's possible to shoot a Survivor high up with the bile bomb. First, have one Survivor stand at a spot where there's elevation, while the Bile bomb user stands below the Survivor. Have the victim jump constantly, make sure to crouch after each jump. While the victim is in the air, have the person crouched below throw the bile at their feet. If done correctly, the victim will be shot up in the air like a catapult. This is very useful in certain survival maps for reaching normally inaccessible areas. [?] It is also very safe because it cannot backfire, as it does not do any damage.
  • If thrown in inaccessible for Common Infected areas (for example, water or rooftops), they will stop spawning and moving.
  • Like any other grenades, Survivor Bots will never pick up the Bile Bomb in normal gameplay.
  • Bile bombs and molotov cocktails can activate alarmed cars, this is because both grenades are made out of glass and can damage the car.
  • It is the only grenade whose icon does not resemble the container. Instead, it is a biohazard symbol.



Primary Weapons
Tier 1 Chrome invert Chrome Shotgun / Pump invert Pump Shotgun / MP5 Invert MP5 / Mac10 invert Silenced Submachine Gun / Uzi invert Submachine Gun
Tier 2 Ak invert AK-47 / Scar invert Combat Rifle / M16 invert M-16 Assault Rifle / SIG Invert SG 552 / Auto invert Auto Shotgun / Spas12 invert Combat Shotgun / AWSM Invert AWP / Hunting invert Hunting Rifle / Steyr Invert Scout / G3 invert Sniper Rifle
Special Tier Grenade launcher inverted Grenade Launcher / M60Icon M60 Machine Gun
Secondary Weapons
Sidearms Pistol inverted M1911 Pistol / Deagle invert Magnum Pistol / Pistol l4d2 inverted P220 Pistol
Melee Weapons Bat invert Baseball Bat / Cricket invert Cricket Bat / Crowbar invert Crowbar / Axe invert Fireaxe / Pan invert Frying Pan / GolfClubIcon Golf Club / Guitar invert Guitar / Katana invert Katana / Knife Invert Knife / Machete invert Machete / Baton invert Nightstick / Icon pitchfork inverted Pitchfork / Icon shovel inverted Shovel
Special Tier Chainsaw invert Chainsaw
Other Weapons
Grenades Bile invert Bile Bomb / Molotov inverted Molotov Cocktail / Pipebomb invert Pipe Bomb
Upgrades L4D2 ammo explosive Explosive Ammunition / L4D2 ammo incendiary Incendiary Ammunition / Laser sight HUD invert Laser Sight
Fixed Weapons MMG Icon Heavy Machine Gun / Minigun icon Minigun
Usable Items Explosive Barrel HUD invert Explosive barrel / Fireworks icon Fireworks / Gas canister HUD invert Gas can / Oxytank icon Oxygen tank / Propane tank icon Propane tank
Special Items Cola Cola / Gnome icon Gnome Chompski
Featured in both games / L4D1-exclusive / L4D2-exclusive (Counter-Strike weapons / PC-exclusive)