Clean hands doctrine

In non-criminal matters, the clean hands doctrine, also called the unclean hands doctrine or dirty hands doctrine, states that a party is required to be free of wrongdoing (come with "clean hands") if it wants the court to issue a ruling in their favour. The "wrongdoing" may consist of breaking the law, or acting unethically, unfairly or in bad faith with respect to the other party of the complaint. The wrongdoing must be directly related to the specific case at hand and not be just "background" misbehaviour. The purpose of the doctrine is to prevent disingenuous parties from benefitting from their own misconduct.

Showing "unclean hands" is an affirmative defence, which the judge has discretion to not approve. If a party raises it, it has the burden of proof to show that the other party is being dishonest. It is generally invoked by a defendant to the lawsuit to avoid liability. But plaintiffs may also use it offensively, too, to deny the defendant the possibility to raise other defences. The doctrine typically applies to equitable remedies only (e.g. requests for an injunction or specific performance), but some jurisdictions also allow application to suits in law (such as those seeking damages).

The clean hands doctrine is rooted in Roman law. Its outlines were made explicit in 18th-century practice of courts of equity in English law, and for that reason it has since become an integral part of common law jurisprudence. Civil law systems also have the related concept of prevention of "abuse of rights". However, scholars cannot agree if the clean hands doctrine is a universal principle of law. In particular, international law is reluctant to adopt the rule in full, although it has not explicitly rejected it, either.