A cosmetic surgery was forced to close after the health watchdog raised concerns about the safety of its practices.
Smethwick's Bearwood Cosmetic Clinic's registration was cancelled by the Care Quality Commission (CQC) last year.
The health watchdog's report into the practice is yet to be published, but inspectors have written to other practitioners expressing concerns.
It found "unsafe practice" and a lack of appropriate training.
The letter from the CQC reveals it has inspected 65 services across the country, about two thirds of independent cosmetic surgery providers and raised concerns about 12.
While some were found to be "providing a very good standard of care", there were a number of areas of concern.
Ted Baker, chief inspector of hospitals, wrote to providers raising particular concern regarding the use of anaesthetic during liposuction.
Inspectors had seen examples of "unsafe practice", he said, and reminded providers that a trained anaesthetist should be present for procedures.
The CQC also warned it had found evidence of staff not having appropriate training, a lack of attention to fundamental safety processes and infection control standards not being followed
The watchdog expects to publish its findings regarding Bearwood Cosmetic Clinic, which was marked as "archived"' on the CQC's website in April, early next month.
It confirmed it began action against the practice, which offered liposuction, Botox and fillers, in November 2018 and it has been closed since December.
The clinic had appealed against the decision, but the challenge was later withdrawn, the CQC said.
The CQC only regulates surgical procedures carried out by healthcare professionals, which would include breast enlargements, liposuction, nose surgery and facelifts but not fillers and Botox.
It advised clients to thoroughly research providers before procedures.
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