The main purpose of the Exclusionary Rule is to prevent illegal search and seizure in relation to criminal cases. The rule prevents the police or lawyers from using evidence in a trial or case that was gained by methods that violate the Constitution.
This law also applies to information gathered improperly under the defendant's Fifth Amendment rights. The Sixth Amendment is also covered under this rule if information is improperly gathered in relation to the defendant's right to counsel. The Exclusionary Rule does not apply in civil cases and is not an independent Constitutional right. The rule is not able to be invoked if the court has assured law enforcement that they have a valid warrant as well, even if this is in error.