A campaign to try to stop mistakes and infections in hospitals from causing accidental deaths is being launched across the NHS in Wales.
It is hoped improving hygiene and drug management could save 1,000 lives over the next two years.
The '1,000 Lives Campaign' aims to spread the good practice of some hospitals to all in Wales, introducing check lists and better communication.
All NHS trusts and local health boards have chosen to sign up to the campaign.
According to the campaign directors, at least one in 10 patients are harmed unintentionally by their treatment, and end up in hospital for longer.
Incidents range from minor allergic reactions to medication, to life threatening mistakes in an operation.
One in 300 patient deaths are actually due to errors in care.
Campaign co-director Dr Jonathon Gray said: "Many of us know of people who have not had the standard of healthcare they need in hospital or primary care.
"Staff in the NHS know this too. We save lives every day. The 1,000 Lives Campaign will help save more."
Abertawe Bro Morgannwg (ABM) University NHS Trust said it had signed up to the campaign - officially launched in Swansea on Monday - to ensure patients receive the safest and most effective healthcare.
Dave Hope, an intensive care consultant at Swansea's Morriston Hospital, said: "This is an important campaign because it is aimed at spreading good practice, not only in intensive care units, but across wards within hospitals, ensuring all patients get the same good standards of care."
He said lessons learned in the intensive care unit, for example, such as reducing infection risks, can be rolled out across other areas of the hospital.
Ann Griffiths, a clinical nurse practitioner and duty manager of Ceredigion & Mid Wales NHS Trust, said: "As nurses we are constantly seeking to improve our practice and do the best we can for our patients.
"This campaign is an excellent way of reinforcing this process."
The campaign is being run as a collaborative, involving the Welsh Assembly Government and other health agencies.
Trusts and local health boards will monitor the impact of the new ways of working.
They will report back on improvements made during the two-year campaign.
It should then be possible to measure the number of lives saved across Wales as a whole.