---
title: "Parol Evidence Rule"
type: Legal Term
source: https://casebriefly.com/legal-terms/parol-evidence-rule
---

# Parol Evidence Rule

The parol evidence rule bars the introduction of extrinsic evidence — oral or written statements made before or at the time of contracting — to contradict, modify, or vary the terms of a fully integrated written agreement. However, parol evidence may be admitted to explain ambiguous terms, prove fraud or duress, establish a condition precedent, or show that the writing was not intended as a complete integration. The UCC takes a more liberal approach in trade usage and course of dealing contexts.

## Related Terms

- acceptance
- unconscionability
- conditions-precedent

## Related Cases

- raffles-v-wichelhaus
- c-j-fertilizer-v-allied-mutual-insurance
- market-street-associates-v-frey

## Example

A buyer and seller sign a written contract for 100 tons of steel. The buyer may not introduce testimony that they orally agreed to 200 tons if the contract is fully integrated.

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Source: [Parol Evidence Rule — CaseBriefly](https://casebriefly.com/legal-terms/parol-evidence-rule)