21 U.S.C. § 152 : US Code - Section 152: Importation regulated and prohibited

Search 21 U.S.C. § 152 : US Code - Section 152: Importation regulated and prohibited

The importation into the United States of any virus, serum,
toxin, or analogous product for use in the treatment of domestic
animals, and the importation of any worthless, contaminated,
dangerous, or harmful virus, serum, toxin, or analogous product for
use in the treatment of domestic animals, is prohibited without (1)
a permit from the Secretary of Agriculture, or (2) in the case of
an article originating in Canada, such permit or, in lieu of such
permit, such certification by Canada as may be prescribed by the
Secretary of Agriculture.