Ho Chi Minh City police said they seized illegal drugs from a bar in District 1 during a raid early Saturday.
More than 100 police officers stormed into the Gold Club on Ho Huan Nghiep Street for a "routine check" as around 400 people danced.
Police said they found 10 ecstasy tablets on the dancing floor and seized five packs of white powdered ketamine from the bar.
They took 200 people who failed to produce identification to a police station for drug testing. Fifteen women and seven men tested positive for banned substances.
According to the police, before they raided the bar, some police officers in plainclothes seized seven ecstasy tablets from the trouser pockets of Le Quang Loc, a 26-year-old employee of the bar, at the lounge.
Loc confessed to the police that he had sold ecstasy tablets to the bar's customers for VND270,000-300,000 (US$13-14) per tablet over the last two months. He sold 10-30 tablets a day.
Loc has been detained for further investigation.
The police have pressed administrative charges of "overtime operation," "insufficient lighting," "allowing customers to use illicit drugs," and "illegal trade in alcohol" against the bar.