35 U.S. Code § 295 - Presumption: Product made by patented process

In actions alleging infringement of a process patent based on the importation, sale, offer for sale, or use of a product which is made from a process patented in the United States, if the court finds—
that a substantial likelihood exists that the product was made by the patented process, and
that the plaintiff has made a reasonable effort to determine the process actually used in the production of the product and was unable to so determine,
the product shall be presumed to have been so made, and the burden of establishing that the product was not made by the process shall be on the party asserting that it was not so made.
Editorial Notes

1994—Pub. L. 103–465 substituted “sale, offer for sale, or use” for “sale, or use” in introductory provisions.

Statutory Notes and Related Subsidiaries
Effective Date of 1994 Amendment

Amendment by Pub. L. 103–465 effective on date that is one year after date on which the WTO Agreement enters into force with respect to the United States [Jan. 1, 1995], with provisions relating to earliest filed patent application, see section 534(a), (b)(3) of Pub. L. 103–465, set out as a note under section 154 of this title.

Effective Date

Section effective 6 months after Aug. 23, 1988, and, subject to enumerated exceptions, applicable only with respect to products made or imported after such effective date, see section 9006 of Pub. L. 100–418, set out as an Effective Date of 1988 Amendment note under section 271 of this title.