Patients are being urged to think carefully before going to the Accident and Emergency department at Pilgrim Hospital.
United Lincolnshire Hospitals NHS Trust has said it is currently experiencing an unusually high demand for beds at the Boston hospital, as well as at Lincoln County Hospital and Grantham and District Hospital.
A spokesman said: “We are asking members of the public to help us at this busy time and ony use A&E if absolutely necessary.”
To cope with demand the hospital has opened additional beds and is working with partner agencies to ensure beds are freed up when possible.