---
kind: "section"
citation: "21 C.F.R. § 338.10"
title: "21"
number: "338.10"
heading: "Nighttime sleep-aid active ingredients."
url: "https://uscodex.org/cfr/21/338.10"
---

# §338.10. Nighttime sleep-aid active ingredients.


The active ingredient of the product consists of any of the following when used within the dosage limits established for each ingredient in [§ 338.50(d)](/cfr/21/338.50.md?p=d):

- (a) **Diphenhydramine hydrochloride.**
- (b) **Diphenhydramine citrate.**

## Notes

### Authority

Authority: 21 U.S.C. 321, 351, 352, 353, 355, 360, 371.

### Source

Source: 54 FR 6826, Feb. 14, 1989, unless otherwise noted.