The sellers were detained during a Thursday night raid in Khaosan Road, a pedestrian street in the capital known for bars and cheap hotels, according to the Khao Sod daily.
They have been charged with selling medicine illegally. The gas can only be used for medical purposes or to fill airbags in cars. Selling drugs without authorization is punishable by a fine and a jail term.
Thailand has been cracking down on vendors of drug-filled balloons in tourist resorts after police became aware of the gas being increasingly used by party revellers to induce hallucinations and euphoria.
