Actor Yoo Ah-in is under police probe for the illegal use of propofol, a powerful anesthetic commonly used for routine surgeries, and has been banned from leaving the country, according to the police on Wednesday.

A drug crime investigation unit under the Seoul Metropolitan Police questioned Yoo on Monday, on suspicions of violating the Narcotics Control Act. The police questioned Yoo over allegations that he was habitually prescribed propofol through repeat visits to several hospitals.

The investigation began when the Ministry of Food and Drug Safety detected frequent propofol prescriptions to Yoo, and reported the case to the police.

The police secured Yoo’s body hair and requested a drug test to the National Forensic Service.

Yoo’s entertainment agency, UAA, admitted that Yoo is under investigation. “Yoo Ah-in was recently questioned by police regarding propofol use. (Yoo) has been actively cooperating with all investigations,” the agency said in an official letter on Wednesday.

Illegal use of propofol can result in up to 10 years in prison or a fine of up to 100 million won ($79,000). A number of influential figures including Samsung Chairman Lee Jae-yong and actor Ha Jung-woo have been fined for illegal propofol abuse.