For the second time in as many months, the largest hospital in the north east has gone on 'protected call'.
This means it cannot accept many cases coming to the Accident & Emergency Department and instead has to divert some patients to other hospitals around the region.
The hospital will remain on protected call until at least tomorrow afternoon.
In a statement, the HSE said the hospital was still experiencing severe pressure.
Trauma, obstetrics and paediatric cases will continue to be admitted to Lourdes.
According to the Irish Nurses Organisation, this morning there were a record number of 45 patients on trolleys in Our Lady of Lourdes Hospital in Drogheda.
The HSE said that in order to relieve the pressure on the hospital's Emergency Department, and in the interests of patient safety, they put Lourdes on protected call from yesterday evening.
As a result, ambulance crews and GPs are being been asked to send adult patients with medical complaints to the Louth County Hospital in Dundalk or Our Lady's Hospital in Navan.
Adult patients with surgical complaints are being diverted to Navan or Cavan General Hospital.
Last month, the hospital was placed on protected call when a then record number of 40 patients were on trolleys around the A&E and corridors nearby.
