Section 11 of Civil Procedure Code deals with the concept of Res judicata. It provides that-No Court shall try any suit or issue in which the matter directly and substantially in issue has been directly and substantially in issue in a former suit between the same parties, or between parties under whom they or any of them claim, litigating under the same title, in a Court competent to try such subsequent suit or the suit in which such issue has been subsequently raised, and has been heard and finally decided by such Court.
Note-Res judicata is a Latin expression or term that means “matter once adjudicated, cannot be re-adjudicated” The doctrine of res judicata technically means that a matter in issue which has already been tried by competent Court, then trial between the same parties in respect of the same matter shall not be allowed. It is a very important doctrine in civil justice system. It emphasises that a subject matter of the suit which has already been decided, is deemed to be decided forever, and cannot be reopened by the same parties
The doctrine of res judicata is based on three maxims 1. Nemo debet bis vexari pro una et eadem causa-no man should be punished/vexed twice for the same cause 2. Interest reipublicae ut sit finis litium-it is in the interest of the State that there should be an end to a litigation. 3. Res judicata pro veritate occipitur-a judicial decision must be accepted as correct.