An "unprecedented" demand for services at the Royal Cornwall Hospital have placed it back on Black Alert status for the fourth time this year.
This is the highest level of alert, which usually means bed capacity has been reached and that patients arriving at A&E will have to be taken to another hospital.
People are being told to stay away unless it is a genuine emergency - and where possible pick up relatives and friends as soon as possible, when they are ready to go home from hospital.
- Read more: What does Black Alert mean?
People are being asked to choose what kind of care they need carefully - the NHS 111 helpline can give advice as to the nearest and most appropriate service.
You can also visit the NHS Choices website.