21 CFR § 20.25 - Retroactive application of regulations.

---
identifier: "/us/cfr/t21/s20.25"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 20.25 - Retroactive application of regulations."
title_number: 21
title_name: "Food and Drugs"
section_number: "20.25"
section_name: "Retroactive application of regulations."
chapter_name: "FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "A"
subchapter_name: "GENERAL"
part_number: "20"
part_name: "PUBLIC INFORMATION"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "5 U.S.C. 552; 18 U.S.C. 1905; 19 U.S.C. 2531-2582; 21 U.S.C. 321-393, 1401-1403; 42 U.S.C. 241, 242, 242a, 242l, 242n, 243, 262, 263, 263b-263n, 264, 265, 300u-300u-5, 300aa-1."
regulatory_source: "42 FR 15616, Mar. 22, 1977, unless otherwise noted."
cfr_part: "20"
---