Greenlaw Grove in Newton Mearns has been served with a formal improvement notice by the Care Inspectorate.
During an inspection on the home which looks after 113 elderly people, many of whom have dementia, found several areas which needed improvement urgently, including staffing numbers, training and registration.
Residents’ hygiene, health and well-being were other areas which required improvement, as well as drug administration.
A previous report found “staff were recording incidents which should have been investigated by the service or referred to social services for further investigation”.
The care home was ordered to provide further training for staff in areas including infection control and medication management by the end of October.
A spokesman for the Care Inspectorate said: “The improvement notice we have issued clearly lays out the improvements we need to see so that the care provided to residents improves quickly.
“We will visit this care home again soon to check on progress and if we are not satisfied that the matters raised are being addressed urgently we will not hesitate to take further action. Everyone in Scotland has the right to safe, compassionate care which meets their needs and respects their rights.
The care home’s management said they were taking “swift action” to ensure standards were met.
A spokesman for the nursing home said: “The results of the recent inspection were far below the high standards we have consistently delivered for our residents over many years and we have taken swift action to put things right.
“We are working closely with the Care Inspectorate and have already made very significant progress.
Anyone with a concern can contact the Care Inspectorate helpline on 0345 600 9527.