Dispel type
Many of the buffs and debuffs in World of Warcraft have a dispel type, which appears in the upper right-hand corner of the tooltip box if you hover your pointer over the buff or debuff icon. The dispel type tells you how the effect can be removed or dispelled. There are 5 main dispel types, 2 that are rarely used, and at least one that is present on tooltips but not targeted by any abilities.
Curse
- Main article: Curse
The ability to curse their enemies is almost exclusively limited to warlocks, although shaman can also curse via 
[Hex]. Druids with 
[Remove Corruption], mages with 
[Remove Curse], and shaman with 
[Cleanse Spirit] can remove them.
Disease
- Main article: Disease
These are usually conditions like 
[Rabies], [Tetanus], and the like and are usually caused by mobs. However, priests can cast 
[Devouring Plague], and certain death knight abilities cause diseases, most notably 
[Blood Plague] and 
[Frost Fever]. Paladins (
[Cleanse]), priests (
[Cure Disease]), and monks (
[Detox] and Mistweavers' 
[Revival]) can remove Disease-type effects from themselves and their allies. The dwarven racial ability 
[Stoneform] will also instantly cleanse the caster of all Disease effects.
Magic
- Main article: Magic (dispel type)
The most common effects are Magic. There are Magic-type buffs (beneficial), as well as Magic debuffs (harmful).
Hunters can use 
[Tranquilizing Shot], shaman can use 
[Purge], and Protection warriors can use 
[Shield Slam] to remove Magic buffs from their enemies. Warlocks may use their Felhunter's [Devour Magic]. Mages can use 
[Spellsteal] to transfer enemy Magic buffs to themselves.
With the appropriate talents, Holy paladins (
[Sacred Cleansing]), Restoration druids ( [Nature's Cure]), and Restoration shamans ( [Improved Cleanse Spirit]) have the ability to remove Magic debuffs from their allies. All Mistweaver monks can remove Magic debuffs from themselves and their allies using [Detox] and [Revival]. The monk talent 
[Diffuse Magic] removes Magic debuffs from the caster.
Priests of all kinds can use 
[Mass Dispel] to simultaneously remove buffs from enemies and debuffs from allies. Priests can also use 
[Dispel Magic] to remove 1 buff from an enemy or up to 2 debuffs from themselves.
Some Magic-type effects are classed as invulnerabilities, and cannot be removed by any of the aforementioned abilities; these include 
[Banish], 
[Ice Block] and 
[Divine Shield]. Only a priest's glyphed [Mass Dispel] or a warrior's 
[Shattering Throw] can remove these more potent buffs.
Poison
- Main article: Poison
Rogues are highly capable of causing Poison-type debuffs and DoTs, but many mobs do as well. Hunter sting abilities are also considered poison debuffs. Druids (with [Remove Corruption]), paladins ( [Cleanse]) and monks ( [Detox] and [Revival]) can remove these. Those with the First Aid secondary skill can also create Anti-Venoms to cure poison, although these are very rarely used at max level. Dwarves can invoke [Stoneform] to cleanse themselves of all Poison effects for free once every two minutes.
Enrage
- Main article: Enrage effect
Rare dispel types
- Stealth: Includes the rogue ability
[Stealth], the druid ability 
[Prowl], and some NPC abilities. The only dispel effect that removes these is the ability of a 
[Gnomish Alarm-o-Bot]. - Invisibility: Displayed as a dispel type, but not dispelled by anything in the game. Includes the mage spells
[Invisibility] and 
[Greater Invisibility]. - Special (npc only): A type that includes only one effect, Kael'thas Sunstrider's Mind Control, which is dispelled by
[Infinity Blade]. 
[Morbent's Bane] could also have dispelled this effect before Patch 4.0.3, since the effect it was designed to dispel (Morbent Fel's Unholy Shield) also had this dispel type.
Typeless effects
There are also many lasting effects which do not have a dispel type; there are no general spells that remove these. However, there may still be hope: the ones that impose a specific mechanic upon the target may be susceptible to removal by certain items and abilities that can remove this specific mechanic (for example, 
[Luffa] and [Stoneform] can remove bleed effects, while [Tranquilizing Shot], 
[Soothe], and 
[Shiv] can remove Enrage effects). Some lasting effects, however, must simply run their course and expire with time.
Most typeless effects can also be removed using the paladin's [Divine Shield] or the mage's [Ice Block].
Reading a Wowhead dispel effect
On Wowhead, a spell entry may include the effect "Dispel" followed by a number in brackets. That number indicates the type of buff or debuff the spell will remove:
- Magic
- Curse
- Disease
- Poison
- Stealth
- (unused)
- Magic, Curse, Disease or Poison
- Special (npc only)
- Enrage
On the next line, the number following "Value:" is the maximum number of effects of this type that will be dispelled. Spells that have the attribute "Remove auras on immunity" remove buffs and debuffs based on their mechanic rather than their dispel type.