Patentable Subject Matter
Congress specifically listed four types of things as patentable:
- Compositions of matter
Discoveries of natural phenomena, products or laws of nature, and abstract ideas are not patentable.
If a patent claim is over an excluded subject matter, it must have an "inventive concept" that transforms the idea into a patent-eligible invention.
You cannot patent food recipes, even though it would seem to fit the requirements. They would have to be trade secrets instead.