Who's Responsible for Cannabis Safety in Japan?

Japan has one of the strictest cannabis regimes in the world, and in December 2024 it got stricter and looser at the same time. A single reform did two opposite-looking things: it made using cannabis a crime for the first time, and it opened the door to cannabis-derived medicine.

So what can you legally buy, and who makes sure it is safe? In Japan, the answer is almost entirely about one number: how much THC is in the product.

The short version: the "cannabis" you can legally buy in Japan is CBD with virtually no THC. How little is allowed depends on the product, and every import has to prove it with a lab report before it reaches a shelf.

What changed in 2024

For decades Japan's 1948 Cannabis Control Act banned the plant but, oddly, never banned using it. The reform that took effect on 12 December 2024 closed that gap and went further:

Using cannabis is now a crime, with penalties for the main offenses raised to up to seven years.

Cannabis-derived medicines are now allowed in principle, regulated like other controlled pharmaceuticals. (For now the pathway is open, but no such medicine has actually been approved for sale yet.)

CBD is judged by its THC content, not by which part of the plant it came from.

That last change is the one that matters for anything you can buy today.

The rule that keeps products "safe": near-zero THC

Before the reform, CBD was only legal if it came from cannabis stalks or seeds. Now CBD from any part of the plant is allowed, as long as the residual THC stays under a strict limit. And the limit depends on the form of the product:

Oils and powders: up to 10 parts per million of THC.

Other products (edibles, capsules, cosmetics, vape liquids): up to 1 part per million.

Drinks and other water-based products: up to 0.1 parts per million, the strictest tier of all.

To put that in perspective, a legal CBD drink in Japan has to be about a hundred times cleaner of THC than a legal CBD oil. Go over the limit and the product is not "CBD" in the eyes of the law; it is illegal cannabis.

Who checks it

Because almost all CBD is imported, Japan's safety net sits at the border, and it is unusually hands-on:

The manufacturer formulates the product to stay under the THC limit for its category.

A testing lab issues a Certificate of Analysis showing the THC level. Japan often will not accept a foreign lab report unless the method meets its standards.

The Narcotics Control Department, part of Japan's health ministry regional bureaus, reviews the paperwork and decides whether the product legally counts as "cannabis" before it is allowed in.

Customs clears only approved shipments, and for anything you eat or drink, a separate food-safety inspection applies.

Only after all of that does a product reach a store or a Japanese website.

The medical door, and why it is still mostly closed

The reform also created a real route for cannabis-based prescription medicine, reviewed by Japan's drug regulator and dispensed under tight controls, plus a new license to grow cannabis for pharmaceutical use. As of now, no cannabis-derived drug has completed that approval and reached patients, though the first candidate, a CBD medicine for epilepsy, entered expedited review in 2026. The legal framework exists; the product on the shelf does not, yet.

What it means for you

Japan is the mirror image of a US dispensary. There is no THC to enjoy in a legal product, and using cannabis can land you in prison. The upside of that severity is that the CBD which does make it to shelves has been filtered through a testing-and-customs process most countries do not run. If you buy CBD in Japan, the safety question is whether the seller can show the Certificate of Analysis that got it past the border.

Curious how this works where cannabis is sold recreationally? See our state-by-state walkthrough of who signs off on a US cannabis lab report at weed-central.com/learn/coa (https://weed-central.com/learn/coa?utm_source=newsletter.weed-central.com&utm_medium=newsletter&utm_campaign=who-s-responsible-for-cannabis-safety-in-japan).

This article is general information, not legal advice. Japan's cannabis rules changed recently and continue to evolve; verify the current requirements before relying on any detail.