Prohibition

Prohibition, in drug law, is a control regime that bans a substance outright — no licensed supply, no authorized possession, no permitted commerce. It sits at one end of a spectrum that also includes regulation (lawful supply under license) and decriminalization (removal of criminal penalties for possession while supply remains unlawful).

The term is a general descriptor rather than a statutory label. It describes the practical effect of placing a substance in the most restrictive tier of a national scheduling regime — typically one enacted to meet the obligations created by the three United Nations drug control treaties.

What it means in practice

Under prohibition, manufacture, importation, supply, and in most jurisdictions simple possession become criminal offences. Research access is tightly restricted and normally requires dedicated government authorization.

A substance enters a prohibitory tier through legislation or administrative rulemaking. In the United States, the Drug Enforcement Administration can place a compound into Schedule I on an emergency basis, ahead of formal rulemaking; permanent placement requires a subsequent scientific and medical review from the Department of Health and Human Services.

Analogue provisions extend prohibition's reach beyond named compounds. The United States Federal Analogue Act treats substances substantially similar in structure or pharmacological effect to a Schedule I or II compound as themselves controlled when intended for human consumption. Comparable clauses exist in other jurisdictions, though the tests for similarity differ.

How jurisdictions vary

Most national prohibition regimes rest on three United Nations drug control treaties: the Single Convention on Narcotic Drugs (1961), the Convention on Psychotropic Substances (1971), and the Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances (1988). Signatory states are obliged to bring listed substances under control, but the form that control takes — and how strictly it is enforced — varies considerably.

Portugal retained prohibition on drug supply after its 2001 reform but decriminalized personal possession of all controlled substances, redirecting cases to administrative panels rather than criminal courts. The Netherlands formally prohibits cannabis supply under its Opium Act while operating a longstanding policy of non-enforcement (gedoogbeleid) for small-quantity sales through licensed coffee shops.

A schedule number does not travel. A substance placed in the most restrictive tier in one country may be unscheduled, prescription-available, or approved for regulated adult use in another.

What is contested

The statutory phrase "no currently accepted medical use" — used in United States law to define Schedule I — is a legal test applied by the Drug Enforcement Administration and the courts. It is not a scientific verdict about the weight of clinical evidence, and it has been applied to substances that simultaneously hold published trial findings or regulatory recognition in other jurisdictions.

Cannabis is the most widely discussed case. It has been listed in Schedule I at the federal level in the United States since the Controlled Substances Act was enacted in 1970, while approved for medical or adult use under state law across much of the country and regulated as a lawful consumer product in several other countries. The federal legal classification and the record of accepted use in those jurisdictions represent two different findings; the encyclopedia records both without adjudicating between them.

Scope and currency

This entry is not legal advice and does not describe the law in any particular jurisdiction. Drug prohibition regimes change — treaty protocols are updated, substances are rescheduled, and national reforms alter the picture continuously.

This entry states the position as of August 2026. For jurisdiction-specific, sourced, and dated information on a particular substance, consult the legal status section on that substance's page, which carries its own jurisdiction, date, and source.