How does the USPTO define ‘composition of matter’ for patent eligibility?

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.

How does the USPTO define ‘composition of matter’ for patent eligibility?

The USPTO defines ‘composition of matter’ as one of the four categories of patent-eligible subject matter under 35 U.S.C. § 101. According to the MPEP 2106.03:

“Compositions of matter” are chemical compounds, mechanical mixtures, gases, and other materials.

This category encompasses:

• Chemical compounds (e.g., new molecules or substances)
• Mechanical mixtures (e.g., alloys or formulations)
• Gases
• Other materials that don’t fit into the other categories

Compositions of matter are typically substances or materials resulting from chemical unions or physical mixtures. They can include both naturally occurring and artificially created substances, although naturally occurring substances must be significantly different from their natural state to be patent-eligible.