Can a Markush group include combinations or mixtures of alternatives?

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.

Yes, a Markush group can include combinations or mixtures of alternatives, but it requires specific language to make this clear. The MPEP 2173.05(h) provides guidance on this:

“If a claim is intended to encompass combinations or mixtures of the alternatives set forth in the Markush grouping, the claim may include qualifying language preceding the recited alternatives (such as ‘at least one member’ selected from the group), or within the list of alternatives (such as ‘or mixtures thereof’).”

For example, a claim might read: “A composition comprising at least one member selected from the group consisting of A, B, C, and mixtures thereof.” This language clearly indicates that the claim covers not only the individual alternatives but also their combinations or mixtures.