Debuff

A debuff is the contrary of a buff. It is an effect that while it persists hampers the target in some way. Among other effects, debuffs frequently lower attributes, hinder the effectiveness of the target's actions, or cause damage over time.

Sometimes the term debuff is also used to describe the act of removing buffs on hostile targets, but it is usual to refer to such an action as a dispel or cure after the common spells that remove such effects. Another popular name for removing debuffs is decurse.

Debuffs come in many varieties and most of them are race/class specific spells or abilities.

Debuffs are also color coded per the table below.

Limitations
There is no effective limit on the number of debuffs that may be applied to a creature at one time. Prior to the release of the Wrath of the Lich King expansion, a single target could have at most 40 debuffs at one time.

Similar debuffs generally do not stack with each other. One prominent exception is damage over time debuffs (DoTs): multiple copies of the same DoT will generally stack when applied by different players, and when applied by the same player to different targets (Living Bomb is a partial exception). As well, many boss monsters can stack several copies of the same DoT on the same player.

Combating debuffs
Classes listed below have abilities to remove certain kinds of debuff, but each can usually only remove certain types of debuff.

Nevertheless, certain encounters introduce unique debuffs that are impossible to remove even if they would ordinarily be countered by the classes below.

Unclassified debuffs
Some debuffs are not classified in any way, and as such can not be dispelled by any class. There are some exceptions to this - some Bleed effects, which are unclassified, can be cured by using a Luffa or the Dwarven racial ability Stoneform. Also, Paladins can dispel nearly any debuff on themselves by using Divine Shield, as can Mages by using Ice Block.

List of shared (non-stacking) debuffs

 * Mortal Wounds
 * Effect: -25% healing received