Left 4 Dead 2 Spitter Guide

Overview
The Spitter can be a powerful part of a good Infected strategy if used properly. By herself she is very weak and nearly useless against a survivor team that is on a constant lookout for this Special Infected. We have compiled some information for you that will hopefully help you not only avoid her wrath more easily as Survivors, but you may also become better at using her in the versus modes.
Hit Points: 100
Main Attack: Acid Spit
Secondary Attack: Scratch
What is the Spitter?
The Spitter is a female Special Infected who spits toxic acid as an Area-of-Effect attack (AOE). She spits on the ground at the feet of the Survivors and will deal lethal damage until they leave the area. When she is killed a pool of acid forms around the body that will also deal damage.
What are some tell-tale signs of the Spitter?
She has a very high-pitched squeal when she spawns and runs around looking for a place to attack. The pool of acid she creates is a near-neon green bubbling puddle that is very hard to miss. The pool of acid is still visible but difficult to see in water and the mud found in Swamp Fever and Hard Rain.
How to defend against the Spitter
The Spitter has very little health (100) so she is easy to kill. After she spits her acidic goo she is very slow to move and run away so you have a good chance to kill her. Clear the common and other Special Infected quickly to be able to spread your group out or move outside the area her acidic pool creates. Do not enter rooms in which you do not have anywhere to climb, leave easily or the acid can cover the entire area. Avoid her spit and the pool around her dead body at all costs as it does deal damage quickly. Do not revive an incapacitated or dead team mate while the Spitter goo is still around.
How to use the Spitter
I have seen some amazing Spitter players and some amazingly terrible players. The best ways to use the Spitter is to initiate an attack or to support an attack. The best times to play support is when other players are covered in Boomer bile or incapacitated.
The Spitter goo can travel a long range depending on the arc you spit, but it will die out quickly and fall straight down once it hits its limitation. The best places to spit are when Survivors are in small rooms, about to go through crowded areas, to ward them into another attack, on gas cans or when they are incapacitated and a team mate is going to try to save them. You can also bounce your spit off ceilings and walls to get those hard to reach areas where there are Survivors. Combine your spit with the other Special Infected to maximize damage potential. Remember that every incapacitation your team deals is worth ten (10) points.

The Spitter is also very useful in scavenge. The Spitter’s acid is able to light gas cans on fire, thus destroying the gas cans that the survivors collected.
Another notable thing is that the spitter’s goo increases damage done to the target the longer it remains in it’s AoE so you shouldn’t try to just spit to see if you can get points on a survivor that’s passing by, the only times you should use the spit when you know it’s not going to do prolonged damage is to block off areas temporarily (for example, scavenge mode generators) or get players camping in a spot.
She is the best
One thing not mentioned is to not spit on downed survivors when no one is trying to save them because affects on downed survivors is negligible. Really only common infected and hunters can quickly kill incapped people.