# controlled substances - Schedule I-V — Postal shipping restrictions by item category

For controlled substances - Schedule I-V, carrier is USPS; restriction type is prohibited; scope is all mail - when distribution is unlawful; conditions is If the distribution of a controlled substance is unlawful under 21 U.S.C. Section 801-971 or implementing regulations, mailing is also unlawful under 18 U.S.C. Section 1716, recorded from its source on 2026-08-04.

- **Item category:** controlled substances - Schedule I-V _(unconfirmed — we could not tie this to the quote below)_
- **Carrier:** USPS _(our reading, not quoted from the source)_
- **Restriction type:** prohibited _(our reading, not quoted from the source)_
- **Scope:** all mail - when distribution is unlawful _(our reading, not quoted from the source)_
- **Conditions:** If the distribution of a controlled substance is unlawful under 21 U.S.C. Section 801-971 or implementing regulations, mailing is also unlawful under 18 U.S.C. Section 1716 _(unconfirmed — we could not tie this to the quote below)_

## What the source says

> the mailing of the substance is also unlawful under 18 U.S.C. § 1716.

## Source

- https://pe.usps.com/text/pub52/pub52c4_020.htm

Last verified: 2026-08-04. Review by: 2027-08-04.
Part of [Postal shipping restrictions by item category](https://referencesource.org/shipping-restrictions-by-class/).