Cornwall Council has suspended placements to Bowden Derra Park in Launceston while it looks into the claims.
The home provides accommodation and services for up to 46 people with mental health needs, learning or physical disabilities.
The Care Quality Commission (CQC) said it inspected the facility on Monday.
It said a report detailing the findings of the inspection would be published in due course.
Cornwall Council said it was investigating "a number of allegations" about the care people receive at Bowden Derra Park.
"NHS Kernow and Cornwall Council are working closely with other commissioners to ensure people remain safe and will be meeting with residents and their families very soon to keep them updated with any developments," it said.
It added no concerns had been raised about anyone being at immediate risk of harm.
A spokesperson for Bowden Derra Park said the "health, safety and wellbeing" of its clients were its top priorities.
It said that a "positive" meeting had been held with Cornwall Council and it was confident the investigation would "conclude swiftly".
Scott Mann, MP for North Cornwall, said he has been contacted by a number of families who have loved ones at Bowden Derra Park.
"Some have been there for many years and others are new residents. One common theme is that they are all extremely happy with the care they receive from Bowden Derra Park," he said.
The report into the last CQC inspection of Bowden Derra Park, in January 2016, gave the service a 'good' rating.
A care home is being investigated over a "number of allegations" about its services.