21 CFR § 520.955 - Florfenicol.

---
identifier: "/us/cfr/t21/s520.955"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 520.955 - Florfenicol."
title_number: 21
title_name: "Food and Drugs"
section_number: "520.955"
section_name: "Florfenicol."
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"
---


# 520.955 Florfenicol.

(a) *Specifications.* Each milliliter (mL) contains 23 milligrams (mg) florfenicol.

(b) *Sponsors.* See Nos. 000061, 054925, and 058198 in § 510.600(c) of this chapter.

(c) *Related tolerances.* See § 556.283 of this chapter.

(d) *Conditions of use in swine*—(1) *Amount.* Administer in drinking water *ad libitum* at 400 mg per gallon (100 parts per million (ppm)) for 5 consecutive days.

(2) *Indications for use.* For the treatment of swine respiratory disease (SRD) associated with *Actinobacillus pleuropneumoniae, Pasteurella multocida, Salmonella choleraesuis* and *Streptococcus suis.*

(3) *Limitations.* Do not slaughter within 16 days of last treatment. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

[67 FR 78357, Dec. 24, 2002, as amended at 72 FR 262, Jan. 4, 2007; 78 FR 52854, Aug. 27, 2013; 82 FR 12169, Mar. 1, 2017]