Kratom is banned in 11 states: Alabama, Arkansas, Connecticut, Indiana, Kansas, Louisiana, Massachusetts, North Dakota, Tennessee, Vermont and Wisconsin.
Massachusetts was the last state to make it illegal, issuing a temporary emergency order in August.
Ten years earlier, the US Drug Enforcement Agency (DEA) had moved to classify kratom as a Schedule 1, the most dangerous level for drugs, calling it “an imminent hazard to public safety”.
But the effort failed a few months later, after the justice department said it received “numerous comments from members of the public challenging” the attempt.
That leaves states to take action, like Arizona, which recently sued a company selling kratom beverage products.
Groups opposed to kratom want states to do more, saying “gas-station drugs are poisoning our communities”.
Pro-kratom groups like the American Kratom Association are pushing for bans against synthetics “posing as natural kratom”.
Internationally, kratom is banned in the UK. In Europe, the laws vary by country.
In Malaysia, where the kratom tree is native, consumption and sale are banned under the Poisons Act of 1952.
