BANGKOK – Thailand has initiated a ban on selling cannabis to individuals without medical prescriptions, three years after being the pioneering Asian nation to decriminalize the plant.

This new regulation, which Health Minister Somsak Thepsutin approved earlier this week, became effective Thursday following its appearance in the Royal Gazette. The rule prohibits stores from distributing cannabis to those lacking a prescription and categorizes cannabis buds as a controlled herbal substance.

A violation could result in a maximum one-year jail term and a 20,000-baht ($614) fine, according to the order.

The Department of Thai Traditional and Alternative Medicine, tasked with overseeing cannabis-related rules, convened a meeting with national officials on Friday to get them ready for the implementation of these changes.

The move to decriminalize in 2022 had boosted Thailand’s tourism and farming industries, and spawned thousands of shops.

But the country has faced public backlash over allegations that a lack of regulation made the drug available to children and caused addiction.

Treechada Srithada, spokesperson for the Health Ministry, said in a statement Thursday that cannabis use in Thailand would become “fully for medical purposes.”

She said shops that violate the order will be closed and the ministry will also tighten requirements for approval of a new license in the future. She said there are curently 18,000 shops that hold a license to sell cannabis.

The ruling Pheu Thai Party previously promised to criminalize the drug again, but faced strong resistance from its former partner in the coalition government, the Bhumjaithai Party, which supported decriminalization.

Bhumjaithai quit the coalition last week over a leaked phone call between Prime Minister Paetongtarn Shinawatra and former Cambodian leader Hun Sen.

The move to restrict cannabis sales came after officials last month revealed that cannabis smuggling cases involving tourists had soared in recent months. Somsak told reporters Tuesday he would like to relist cannabis as a narcotic in the future.

Thailand’s Office of the Narcotics Control Board said a study conducted by the agency last year found the number of people addicted to cannabis had spiked significantly after it was decriminalized.

A group of cannabis advocates said Wednesday that the change in regulations was politically motivated and that they will rally at the Health Ministry next month to oppose the change and any attempt to make it a criminal offense again to consume or sell cannabis.