21 CFR § 520.852 - Estriol.

---
identifier: "/us/cfr/t21/s520.852"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 520.852 - Estriol."
title_number: 21
title_name: "Food and Drugs"
section_number: "520.852"
section_name: "Estriol."
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: "520"
part_name: "ORAL DOSAGE FORM NEW ANIMAL DRUGS"
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. 360b."
regulatory_source: "40 FR 13838, Mar. 27, 1975, unless otherwise noted."
cfr_part: "520"
---


# 520.852 Estriol.

(a) *Specifications.* Each tablet contains 1 milligram (mg) estriol.

(b) *Sponsor.* See No. 000061 in § 510.600(c) of this chapter.

(c) *Conditions of use in dogs*—(1) *Amount.* Administer at an initial dose of 2 mg per dog per day. The dosage may be titrated to as low as 0.5 mg per dog every second day, depending on response.

(2) *Indications for use.* For the control of estrogen-responsive urinary incontinence in ovariohysterectomized female dogs.

(3) *Limitations.* Federal law restricts this drug to use by or on the order of a licensed veterinarian.

[76 FR 78150, Dec. 16, 2011]