Law and equity courts are combined in federal and many state courts and the form of action in civil cases is known as a civil action.  Some states retain separate law and equity courts, and specific rules govern the chancery court.   In such states where actions in law and suits in equity are separately brought, if one of two pending cases is in equity and the other is at law, one cannot be pleaded in abatement of the other.  The equity courts have peculiar nature and extent of the jurisdiction.

The general rule is that a court will not allow a defendant to be vexatiously proceeded against and a second suit under all the same circumstances as the first and in the same jurisdiction is necessarily considered as vexatious. However, the court will not unduly restrict the rights of plaintiff in pursuing his several remedies.  Thus a suit pending in a court of equity cannot be pleaded in abatement of a subsequent action at law.  [Simon v. Pyrites Co., 32 Del. 581, 583 (Del. Super. Ct. 1925)].  However, the court may refuse to abate in equity or in law  when the remedies available in the actions are dissimilar or that a judgment in one suit does not operate as bar to the other.