A spokesperson for the Care Inspectorate said: "An inspection has identified serious and significant concerns at Baillieston Care Home in Glasgow.
"We understand this is a difficult and distressing time for residents of the care home, their loved ones and staff at the home.
"However, our first priority is always the health and wellbeing of residents.
"Because of our concerns we have issued an Improvement Notice which sets out the significant improvements that must be made, swiftly, so that the care experienced by residents is of a standard they have a right to expect.
"We are communicating closely with partners including the local health and social care partnership to ensure those affected experience appropriate support during this difficult time.
"Anyone with a concern can contact us on 0345 600 9527."
The Improvement Notice can be read here.