Watchdog the Care Quality Commission (CQC) said it was liaising with bosses at Belmont Grange home in Durham after being made aware of “concerns”, with Durham County Council also investigating.
The nature of the concerns are not fully known at this time, but the home admitted a “very serious medication incident” occurred last month, which it reported to the CQC and council.
Bosses said a “number of staff” had left the home since.
In a statement a spokesperson said: “The focus of the management team at Belmont Grange Nursing Home is always on the wellbeing of our residents and staff. That will always remain the case.
“Following a very serious medication incident in September, a number of staff have left the team at Belmont Grange. The incident was appropriately reported to the CQC and Durham County Council safeguarding team.
“Our focus is always on the residents and making sure that their care is safe. Having spoken to nearly all the staff in one-to-one meetings in the last week, I am confident that the staff remain focused on providing the best care possible.”
The home, on Broomside Lane, was last inspected by the CQC in January 2023, when it was rated “good”.
The CQC said: “Our priority, at all times, is the health and wellbeing of people using health and social care services, and all information we receive informs our monitoring of services and future inspections.”
Durham County Council has also launched enquiries after being contacted by two people about the home.
“Lee Alexander, the council’s head of adult care, said: “We take all reports we receive of this nature extremely seriously and our practice improvement and commissioning officers visit homes and speak to staff to look into matters raised with us.
“We also liaise with the Care Quality Commission and North East and North Cumbria NHS Integrated Care Board where appropriate.
“In this case, our enquiries are continuing so it would be inappropriate to comment further.”