In recent months, he said at least four clients were taken to hospital because of methods used at the centre.
The Narconon Trois-Rivières is one of dozens of similar centres in the U.S. and around the world where the detox treatment is inspired by the teachings of Scientology.
Mauricie regional health agency director Marc Latour said Narconon Trois-Rivières advertised an 80 per cent success rate and charged $25,000 for its program.
Latour said the centre was dangerous for patients and violated many of the criteria regulating Quebec's rehab centres.
He said there was no medical supervision and no scientific basis to the treatment.
Latour said patients went cold turkey, then underwent lengthy sauna detox sessions designed to sweat out drugs and took an unhealthy amount of vitamins.
An Ontario women, who asked to remain anonymous, says her son has now been sent to a Narconon centre in the U.S. (CBC)An Ontario woman, who asked to remain anonymous, spent thousands of dollars for her son to kick an addiction to the drug OxyContin.
But this weekend, just three weeks into his treatment, she had to drive back to the centre.
"The students had to basically get out [as soon as possible]," she told the CBC. "There was no information at that point."
Her son, along with half of the 34 people who were at the centre when it was shut down, have been sent to Narconon centres in the U.S.
The centre issued a statement Tuesday night, defending its rehab model and calling on the department of health to support more solutions, not fewer.
"People with drug problems and their families should have a right to choose the program that works for them as these days there are many good alternative programs," it said.
The centre also said it is willing to make needed corrections.
In an interview earlier this month, a spokesperson said the centre's treatment goes hand-in-hand with Scientology teachings and that 1,200 addicts have left the centre drug-free since it opened in 2005.