|Part of the common law series|
|Defenses against formation|
|Excuses for non-performance|
|Rights of third parties|
|Breach of contract|
|Related areas of law|
|Other common law areas|
Clean hands, sometimes called the clean hands doctrine or the dirty hands doctrine, is an equitable defense in which the defendant argues that the plaintiff is not entitled to obtain an equitable remedy because the plaintiff is acting unethically or has acted in bad faith with respect to the subject of the complaint—that is, with "unclean hands". The defendant has the burden of proof to show the plaintiff is not acting in good faith. The doctrine is often stated as "those seeking equity must do equity" or "equity must come with clean hands". This is a matter of protocol, characterised by A. P. Herbert in Uncommon Law by his fictional Judge Mildew saying (as Herbert says, "less elegantly"), "A dirty dog will not have justice by the court".
The clean hands doctrine is used in U.S. patent law to deny equitable or legal relief to a patentee that has engaged in improper conduct, such as using the patent to extend monopoly power beyond the claims of the patent.
A defendant's unclean hands can also be claimed and proven by the plaintiff to claim other equitable remedies and to prevent that defendant from asserting equitable affirmative defenses. In other words, 'unclean hands' can be used offensively by the plaintiff as well as defensively by the defendant. Historically, the doctrine of unclean hands can be traced as far back as the Fourth Lateran Council.
Relation to equitable remedies
Equitable remedies are generally remedies other than the payment of damages. This would include such remedies as obtaining an injunction, or requiring specific performance of a contract. Before the development of the courts of equity in England, such remedies were unavailable in the common law courts, which were usually under the aegis of the local ducal noble, whereas equity flowed from the circuit-riding presence of the King's Chancellor who brought along his retainers to enforce his orders (in this sense, the development of the equity courts was a political effort by the Crown to further limit the power of local nobles). Such remedies were developed in the equity courts, as the payment of damages was often not a sufficient remedy for a plaintiff in certain circumstances. For example, if a landowner polluted the land of the neighbor, the common law tort of nuisance would only allow the innocent party to recover damages. Common law had no remedy that would force the defendant to stop the pollution. Equity courts developed such a remedy, the injunction, that provided an ongoing bar to the activity that caused the damage, as well as affirmative orders called mandamus which compelled a directed party to do a certain thing (which the Chancellor could enforce while there).
Equity courts realized that such extraordinary remedies were only justified in extraordinary cases, and would generally not grant such a remedy where damages were sufficient to make the plaintiff whole. For example, if a car dealership broke a contract of sale and refused to deliver a particular car, which now could only be obtained for $10,000 more than what the plaintiff was willing to pay, the courts would merely award the plaintiff $10,000 (in addition to the original amount paid, if it had already been paid). It would not force the dealer to obtain exactly the same car and sell it to the plaintiff. However, if the subject matter of the sale were unique, such as a particular work of art or real estate, the court would order specific performance and require the sale.
However, equity courts also realized that these extraordinary remedies were subject to abuse. For example, if a doctor had signed a non-compete clause with a clinic, the non-compete clause might prevent the doctor from earning a living if he left the clinic's employment. As such, the court will generally only grant these remedies on the strictest terms. If there is any indication that the plaintiff seeking the remedy had acted in bad faith, either prior to the commencement of the litigation or afterwards, the court will generally not grant the remedy. For example, if the doctor left the clinic because it was involved in insurance fraud, a court would most likely refuse to enforce the non-compete agreement by issuing an injunction, although it might allow the clinic to recover damages if they did lose business to the doctor. Much of the various limitations, often expressed as "maxims of equity", arose from the sheer physical fact that the Chancellor and his merry band of enforcers would soon be moving on to another locale, and thus equity tended to be careful in allowing access to its powerful remedies and to order only those things which would be quickly or effectively enforced.