21 CFR § 335.3 - Definitions.

---
identifier: "/us/cfr/t21/s335.3"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 335.3 - Definitions."
title_number: 21
title_name: "Food and Drugs"
section_number: "335.3"
section_name: "Definitions."
chapter_name: "FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "D"
subchapter_name: "DRUGS FOR HUMAN USE"
part_number: "335"
part_name: "ANTIDIARRHEAL DRUG PRODUCTS FOR OVER-THE-COUNTER HUMAN USE"
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. 321, 351, 352, 353, 355, 360, 371."
regulatory_source: "68 FR 18881, April 17, 2003, unless otherwise noted."
cfr_part: "335"
---


# 335.3 Definitions.

As used in this part:

(a) *Antidiarrheal.* A drug that can be shown by objective measurement to treat or control (stop) the symptoms of diarrhea.

(b) *Diarrhea.* A condition characterized by increased frequency of loose, watery stools (three or more daily) during a limited period (24 to 48 hours), usually with no identifiable cause.

(c) *Travelers' diarrhea.* A subset of diarrhea occurring in travelers that is most commonly caused by an infectious agent.

[68 FR 18881, Apr. 17, 2003, as amended at 69 FR 26302, May 12, 2004]