What makes a Markush grouping proper?

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.

A Markush grouping is considered proper if the members of the group share both:

1. A “single structural similarity”
2. A common use

This requirement can be met in two ways:

1. The alternatives are all members of the same recognized physical or chemical class or the same art-recognized class, and are disclosed in the specification or known in the art to be functionally equivalent and have a common use.
2. The alternatives share both a substantial structural feature and a common use that flows from the substantial structural feature.

As stated in the MPEP: A Markush grouping is proper if the members of a group share a single structural similarity and a common use. See subsections II – IV, below, for guidelines regarding the determination of whether a Markush grouping is improper.