A combined force of police, military and anti-narcotics officials raided the offices of the Khao Kwan Foundation in Suphan Buri on Wednesday 3 April 2019, seizing about 200 marijuana plants along with cannabis oil, dried marijuana seeds and marijuana powder.[1] Some foundation staff were held in police custody on charges of illegal possession of narcotics, and a summons was issued for foundation president Decha Siriphat to report to police in Suphan Buri on the same charge.[1] Decha was in Laos on a study tour at the time.[1]

Decha, a prominent practitioner of traditional medicine, returned to Bangkok on 9 April and called the arrest of his aide Pornchai Chulert an act of bullying.[2] He said he had been making cannabinoid medicines for more than a decade and distributing them to patients in need, and that he had sent a coordinator to register with the Food and Drug Administration before leaving for Laos.[2] The registration was turned down because officials said he could not prove he was a traditional medicine practitioner, and officers raided the office and seized the medicines instead.[2]

The raid drew a backlash during the amnesty period for medical cannabis users, which ran until 19 May 2019.[2][3] The Office of the Narcotics Control Board later returned the seized plants and extracts and advised the foundation to reorganise its distribution as a proper research project.[4] Prime Minister Prayut Chan-o-cha instructed the public health ministry and educators to support the foundation’s research, in a rebuke of the raiding officials.[4]