Hong Kong authorities have revealed they made their first seizure of a potentially addictive herbal substance just weeks after it was banned. Customs officers discovered 2.5 tonnes of kratom being shipped from Banten in Indonesia to a trading company in Florida via Hong Kong, where it arrived on August 29, according to a source. The kratom was in powder form and contained in vacuum-sealed bags inside 124 boxes. The consignment, worth an estimated HK$6.67 million (US$856,700), was declared as Mitragyna speciosa , the scientific name of the kratom tree, and no attempt had been made to disguise the bags. The nature of the substance was confirmed on Thursday when the major active ingredient mitragynine was detected, and while no arrests had been made, a local office of an Indonesia-based logistics company was being investigated, the insider said. “We will continue to pay attention to consignments from high-risk countries including Indonesia,” the insider said. The Customs and Excise Department reminded the public that kratom was illegal in Hong Kong and companies should pay attention to updates to the official list of contraband items. Kratom, also known as ketum, is made from the leaves of the Mitragyna speciosa tree native to parts of Southeast Asia, including Indonesia and Thailand. The leaves contain chemical compounds that can act either as a stimulant when consumed in small doses or a sedative when taken in larger quantities. Hong Kong takes a hard line on kratom, the ‘herbal heroin’ Long used in traditional medicine in the region, kratom has in recent years appeared in the United States and other places, where users say it can lift their mood, relieve pain and treat addiction to opioids. A study released this year by New York University’s Grossman School of Medicine estimated the US had about 2 million kratom users. Researchers identified 44 deaths in 2017 that could be linked to the drug, but many cases could not be fully investigated because of limited information. Kratom is legal at the federal level in the United States, although several states and cities have banned the substance. It remains legal in all of Florida, except for Sarasota County. Sixtyfold increase in seizure of drugs in Hong Kong Many countries have outlawed the substance, and Hong Kong followed suit when it added the two active ingredients in kratom – mitragynine and 7-hydroxymitragynine – to the list of banned substances under the Dangerous Drugs Ordinance on August 13. Indonesia, believed to be the source of more than 90 per cent of the world’s supply, has banned domestic use of kratom but will allow it to be farmed and exported until next year. The source said authorities would continue to monitor shipments for kratom, believing traders in Indonesia would try to race against time to clear their stocks. Authorities seized 15 tonnes of kratom in three consignments in August last year, according to the latest figures about the drug.