The CQC has asked the regulator of foundation trusts, Monitor, to take action.
An expert taskforce will be sent into the trust with a remit to drive rapid improvements in patient care.
Monitor chairman Dr William Moyes said: "We will be reviewing the trust's performance regularly and in detail - if we don't see measurable results quickly, we'll take further action."
Most of the inpatient care at the trust is provided at Basildon University Hospital, which has 777 beds.
Outpatient care is provided at Orsett hospital in Grays.
The trust was one of the first in England to be granted foundation trust status in 2004. That gives the trust greater freedom to manage its finances.
The independent hospital analysis website Dr Foster has found the Essex trust to have a hospital standardised mortality ratio of 136.
This means the rate of death among patients at the trust is a third higher than would be expected by looking at national figures, after adjusting for patients' age and the severity of their illness.
This is likely to prompt comparisons with Stafford Hospital where similar concerns were raised about a higher than expected mortality rate.
After internal investigations at Stafford failed to find a problem, an independent inspection found serious failings in emergency care.
Cynthia Bower, CQC chief executive, said swift action was needed to "nip problems in the bud".
She said: "Our work has uncovered serious failings. The trust has high mortality rates for emergency admissions and we have found evidence of significant problems in different parts of the organisation.
"The trust has taken our concerns seriously but improvements are simply not happening fast enough.
"Our confidence in the management's ability to deliver on commitments and to turn the situation around has been severely dented."
Health Minister Mike O'Brien said: "Patient safety must be a top priority for the NHS and all patients deserve the highest quality of care."
"We expect these issues to be dealt with quickly and effectively to ensure high quality, safe care for patients."
Andrew Lansley, shadow health secretary, said: "I am extremely disturbed by this news and the effect that these shocking conditions may have had on patients.
"When the appalling standards of care at Stafford Hospital were revealed we were assured by Labour Ministers that it was "an isolated case" - that sort of complacency is simply not good enough."
Norman Lamb, Liberal Democrats health spokesman, said: "If these reports are accurate then it appears there has been a shocking failure in the standards of care at this hospital.
"People have a right to know how on earth a hospital can be rated 'good' a few weeks before such serious failings come to light."
Katherine Murphy, director of the Patients' Association, said: "Yet again we find patients being let down appallingly.
"Lack of monitoring, lack of help with feeding, lack of dignity. How many times do the public need to keep hearing about this before the government is embarrassed enough to do something about it?
"The evidence was there but not acted on. That is completely unacceptable. The system of regulation and supervision needs to be urgently reformed."
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