Thailand is further tightening control of cannabis by banning stores from selling the herb without a prescription.
Thailand became the first country in Asia to decriminalise cannabis in 2022, which boosted Thailand's tourism and farming, and spawned thousands of shops.
But the country has faced public backlash over allegations that under-regulation has made the drug available to children and increased addiction rates.
The ruling Pheu Thai Party previously promised to re-criminalise the drug, but faced strong resistance from its former partner in the coalition government, the Bhumjaithai Party.
But last week, the Bhumjaithai Party, which supported fewer controls, quit the Coalition over a leaked phone call between Cambodia's former leader and Thai PM Paetongtarn Shinawatra, which exposed her apparent mishandling of cross-border tensions.
On Tuesday, Thailand's health minister, Somsak Thepsutin, signed an order that banned shops from selling cannabis to customers for recreational use.
"Cannabis will be classified as a narcotic in the future," he said.
The order also sought to reclassify cannabis buds as a controlled herb, but did not detail any penalty for violations.
Phanurat Lukboon, secretary-general of the Office of the Narcotics Control Board, said his agency was ready to study and implement the regulation changes.
He also said a study done by his agency last year found the number of people with cannabis addiction spiked significantly after it was decriminalised.
The changes will take effect when it is published in the Royal Gazette, but it remains unclear when that will happen.
Government spokesperson Jirayu Houngsu said unregulated access to cannabis created serious social problems, particularly for children and young people.
"The policy must return to its original goal of controlling cannabis for medical use only," he said in a statement.
Reversing a billion-dollar industry
The tightening regulations have left some cannabis industry members like Punnathat Phutthisawong, who works at a Bangkok dispensary, stunned.
"This is my main source of income," Mr Phutthisawong, aged 25, told Reuters.
"Many shops are probably just as shocked because a lot of them invested heavily."
Australian Daniel Wolf was one of many tourists visiting cannabis shops on Bangkok's Khao San Road.
"There are shops everywhere, so how do they reverse this? I don't think they can, it's absolutely insane."
The Thai Chamber of Commerce previously estimated the industry, which included medicinal products, could be worth $1.8 billion by 2025.
Cannabis activist Chokwan Kitty Chopaka said the sector could have transformed Thai agriculture, medicine, and tourism, but uncertainty and policy reversals have stymied any sustainable growth, said
"The cannabis industry has become a hostage to politics," she said.
AP/Reuters
