Thai authorities are cracking down on vendors in Bangkok's main backpacker district selling cheap doses of balloons filled with nitrous oxide, or laughing gas, to tourists.
Eight vendors have been arrested since police first noticed the trend a few weeks ago along Khao San Road, a pedestrian street lined with bars and cheap hotels, Pol Lt Col Pitiphan Kridakorn said Monday.
Each dose sells for about 130 baht, or US$4.
Pol Lt Col Pitiphan said the sale of drug-filled balloons started in popular beaches, such as Koh Samui, Pattaya and Koh Phangan - an island known for "full moon" parties fuelled by drugs and alcohol.
He said police are trying to curb sales of the drug-filled balloons in the capital before it gains wider popularity.
Illicit sales of nitrous oxide could cause harmful side effects to users and give the country a negative image, he said.
Those arrested face up to five years in prison and a $300 fine for selling medicine without authorisation.
Foreign and Thai tourists dance during the monthly full moon party on the beach in Koh Phangan, southern Thailand. (EPA file photo)