What are examples of permissible negative limitations in patent claims?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

Permissible negative limitations in patent claims can include:

• Excluding an element or step that is not part of the invention
• Describing what the invention is not, to clarify its scope
• Distinguishing the invention from prior art

The MPEP 2173.05(i) states: “If alternative elements are positively recited in the specification, they may be explicitly excluded in the claims.” For example, if a specification describes both metal and plastic as possible materials, a claim could state “wherein the article is not made of metal.”

It’s important to note that the negative limitation must have basis in the original disclosure and not introduce new matter.