The Care Quality Commission has rated the Falmouth Road Group Practice as 'inadequate' and has placed the surgery under special measures after inspectors visited in April.
CQC inspectors found that the practice was failing to manage medicines correctly, and provided poor access to appointments with long waiting times that could be putting patients at risk.
The inspection report also criticised Inadequate governance arrangements and a lack of effective processes for recruitment and training.
"It is essential that the Falmouth Road Group Practice takes action to address the concerns we identified during the last inspection," said Ursula Gallagher, deputy chief inspector of primary medical services.
"The provider has a responsibility to ensure that all patients are safe and have access to care that meets their needs.
"When we are faced with a practice that is failing to care for patients properly, our first instinct is to work with the provider to ensure that the service improves.
"We will re-inspect the surgery within six months to check whether sufficient improvements have been made. If sufficient improvements have not been made and there remains a rating of inadequate for any key question or overall, we will take further action which may include closure."