Healing items

Healing items are those used to restore lost health, be it a temporary health boost or a permanent restoration. They can be found in ambulances or randomly throughout the level, but are most often found inside of first aid stations. First aid stations may contain up to 4 bottles of pain pills, but there is also a chance that they contain first aid kits instead, depending on how well the Survivors are doing and the difficulty level. First aid stations found in safe rooms always contain first aid kits.

First aid kit


The first aid kit, colloquially known as a med kit or health pack, is used to heal any damage the Survivors might take during a campaign. When carried by Survivors, it is held on like a backpack with no visible straps holding it.

Defibrillator


The Defibrillator is an item introduced in Left 4 Dead 2. It can be used to revive dead teammates. The defibrillator replaces the health kit and is a one time use item. Its symbol is a lightning bolt.

Pain pills


Pain pills, unlike the First aid kit, will only give the user 50 temporary points of health when taken. When carried by Survivors, it is held on the Survivors right hip, probably on the belt.

Adrenaline injectors


The Adrenaline injector (or the syringe) is included in Left 4 Dead 2. They use pain pills' slot and give you 25 temporary health plus they make you immune to melee fatigue and the horde's slowing melee attacks, as well as increase your movement speed a great deal for a short period of time. In addition to all of this, Adrenaline also increases your running speed a great deal even when healthy and speeds up the time to use a defibrillator, health kit healing, and reviving a fallen survivor. A player on full health can take an Adrenaline shot to run circles around a tank. A player with low health will temporarily have the ability to run at normal speed. Adrenaline can bypass much of the slowing effects of water, such as in the Hard Rain campaign. Adrenaline is also recommended to clear the Gong Show achievement. Adrenaline is mainly useful if used with strategy and has several advantages over the standard pain pills.

Behind the Scenes
Early screenshots show that the First Aid Kit has a more boxlike shape, didn't look like it was made out of soft materials and had a carrying handle at one time. This design can be still be seen in the final version's First Aid Kit icon.

Early videos showed, it was possible to share medkits like pills instead of healing them. (As seen as in this video at 0:36)

Trivia

 * Sprays of the first aid station have become widely available online and may look fairly convincing at a distance.
 * An interesting note is that in Team Fortress 2, another Valve game, pain pills make an appearance on an upgraded dispenser.
 * A poster in The Terminal advertises these specific pain pills, saying "Yes, we've got... Pills Here!"
 * The design of the bottle is based off of Target brand Ibuprofen.
 * Even whilst holding pain pills or a First-Aid kit, Survivors can still use their flashlight. This is odd as there is nowhere for the light source to emanate from.
 * Since hitting the shelves, Left 4 Dead's "Pills here!" became an instant Internet phenomenon/meme, millions of fans claiming that the Survivors were addicted to these over-the-counter pain relievers (or "peelz") with an extensive focus on Louis and Bill, with Louis being portrayed as overly obsessed with them, and often repeating the phrase "grabbin' peelz".
 * In the game, Survivors swallow the entire bottle of pain pills at once. However, if someone were to do this in real life, they would likely die from an overdose soon after, or choke on the pills considering the Survivors don't ingest them with water. Plus, Ibuprofen usually takes around 20-30 minutes to actually start relieving pain, with a recommended dose of no more than 6 tablets per day, where in Left 4 Dead, the pills take affect immediately.
 * It is possible for a merciful Director to change a bottle of pills into a first-aid kit, even if a Survivor has already seen the pills.
 * Pain pills are attached to the Survivors' belts with no visible strap holding them. Likewise, the first aid kit stays on the their backs with apparently no straps keeping them on.
 * After using a first-aid kit, small bands of gauze will appear on the right arm and left thigh or the target, but disappear a couple seconds later.
 * The First Aid Kit, like the new P220 pistol in Left 4 Dead 2, had no walking animation, staying still on the screen when moving.
 * The health pack is an Avatar Award for Xbox 360. Similar to achievements, awards present the player with a new item or article of clothing they can apply to their Xbox 360 Avatar. The requirement for the health pack is surviving each of Left 4 Dead 2's campaigns.