THC Classified as Illegal Narcotic in Japan; Authorities Urge Caution When Purchasing Goods Overseas

The Yomiuri Shimbun

16:47 JST, September 4, 2025

Tetrahydrocannabinol (THC), a compound found in cannabis, is classified as a narcotic under Japanese law.

Police searched the home of Takeshi Niinami, then chairman of Suntory Holdings Ltd., on the suspicion that Niinami had bought supplements containing THC. He claims he bought a supplement containing a legal substance known as CBD, another compound derived from cannabis.

However, some CBD-related products may contain THC, and authorities are urging consumers to check carefully before making a purchase.

THC is believed to cause physical problems such as hallucinations and impaired memory and learning capacity. According to the Health, Labor and Welfare Ministry, the government set quantitative limits on THC last year through such steps as revising the Narcotics and Psychotropics Control Law, thereby prohibiting the export, import, possession and use of supplements that exceed a certain residual amount of THC.

CBD itself is harmless. In Japan, it is used in supplements to reduce stress and enhance sleep, and in cosmetics. However, in the past some products that used CBD were found to also contain THC, underscoring the difficulty of ensuring the safety of CBD-related products.

Some products may contain compounds not listed on their labels. A senior ministry official warned: “People need to recognize the risks, especially when purchasing products overseas. We recommend that they carefully check the details before buying.”