21 CFR § 556.240 - Estradiol and related esters.

---
identifier: "/us/cfr/t21/s556.240"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 556.240 - Estradiol and related esters."
title_number: 21
title_name: "Food and Drugs"
section_number: "556.240"
section_name: "Estradiol and related esters."
chapter_name: "FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "E"
subchapter_name: "ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS"
part_number: "556"
part_name: "TOLERANCES FOR RESIDUES OF NEW ANIMAL DRUGS IN FOOD"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "21 U.S.C. 342, 360b, 371."
regulatory_source: "84 FR 32993, July 11, 2019, unless otherwise noted."
cfr_part: "556"
---


# 556.240 Estradiol and related esters.

(a) [Reserved]

(b) *Residues.* Residues of estradiol are not permitted in excess of the following increments above the concentrations of estradiol naturally present in untreated animals:

(1) *Cattle.* (i) Muscle: 0.2 ppb.

(ii) Liver: 0.6 ppb.

(iii) Kidney: 1.2 ppb.

(iv) Fat: 1.2 ppb.

(2) [Reserved]

(c) *Related conditions of use.* See §§ 522.840, 522.850, 522.1940, 522.2343, 522.2477, and 522.2478 of this chapter.

[84 FR 32993, July 11, 2019, as amended at 87 FR 17947, Mar. 29, 2022]