ROMULUS – U.S. Customs and Border Protection detected and seized roughly $4 million worth of ketamine at Detroit Metro Airport.

According to a CBP press release, a United Kingdom citizen flew in from France on Dec. 13 and was selected for secondary inspection. A search of two large suitcases reportedly revealed plastic bags filled with large white crystals.

The man said the suitcases were packed by a family member.

CBP said the substance was tested and revealed to be 110 pounds of ketamine, which has an estimated street value of more than $4 million.

Under federal law, the agency is required to destroy most seized drugs and retain samples as evidence for criminal prosecutions. Officers didn’t let the traveler enter and he was returned to France, according to a news release.

According to the Drug Enforcement Administration, most of the ketamine illegally distributed in the U.S. has been diverted or stolen from legitimate sources, including veterinary clinics, or smuggled into the country from Mexico.

Ketamine, a Schedule III controlled substance, has been approved by the FDA as an anesthetic since the 1970s. It is accepted for medical use, but the drug — which has been abused for its hallucinogenic effects — is known for its use in nightclub and party culture. A ketamine overdose can cause unconsciousness and dangerously slowed breathing, the federal Drug Enforcement Agency has warned.

Friends actor Matthew Perry died in October from the acute effects of ketamine, according to the results of an autopsy released earlier this month by the Los Angeles County medical examiner. Before his death, Perry received ketamine infusion therapy for depression and anxiety, the autopsy report said.

Perry’s last treatment was a week and a half before his death. Based on the levels of ketamine in his blood, the coroner determined that his cause of death was not from his prior infusion therapy, but rather from ketamine taken in some other manner. Ketamine is usually metabolized in a matter of hours.

CBP officers and agents seized an average of 2,895 pounds of dangerous drugs every day at and between our nation’s air, sea, and land ports of entry, according to the press release.

Travelers are urged to check CBP’s current regulations if they’re unsure what they can bring into the United States.