Cause of action

In the law, a cause of action is a recognized kind of legal claim that a plaintiff "pleads" or "alleges" in a complaint to start a lawsuit. Examples are: "breach of contract"; "personal injury"; "fraud"; "defamation." "Cause of action" encompasses both the "legal theory" of what legal wrong the plaintiff claims to have suffered and the "remedy," which is what a court is allowed to order the defendant to do to compensate the plaintiff for that wrong.

The points a plaintiff must prove to win a given type of case are called the "elements" of that cause of action. (For the cause of action of "negligence," for example, the elements are (existence of a) duty, breach (of that duty), causation (by that breach), and damages (incurred by the plaintiff).) If a complaint does not allege facts to support every element of the cause of action it describes, the court will dismiss the complaint for "failure to state a claim" for which relief can be granted.

The respondent to a cause of action may plead denials or affirmative defenses. Some defenses, such as a lack personal or subject matter jurisdiction may not be pleaded and may be raised at any time.