The medical regulator said it would be taking enforcement action against Dr Bijan Saha but no further details have been revealed due to legal reasons.
Saha has been found guilty of putting his patients at "unacceptable levels of risk" at his practice in Sittingbourne in Kent by the Care Quality Commission (CQC).
Michele Golden, CQC's head of GP inspection for the UK's south region, said: "The issues that we have identified at Dr Saha's practice are very serious and we'd urge anyone who uses it to read our full report.
"People using this practice are currently at unacceptable levels of risk - and keeping them safe is a job for all of us."
A spokesperson added that Saha was still practising but "under very close supervision from local health bodies including the clinical commissioning group (CCG)".
During an unannounced inspection in March, inspectors found the practice failed to meet UK national standards of care in 11 areas.
"Repeat prescriptions were issued without reviews having taken place and were often printed by administrative staff on the verbal instructions of Dr Saha. This procedure had led to a prescribing error which could have had very serious consequences for the patient concerned," the CQC found.
Katherine Murphy, chief executive of the Patients Association, said: "These findings are shocking and cause a great concern to us.
"GPs are the first port of call for patients and to be faced with such poor quality of service is completely unacceptable.