Patients who complain about the NHS need to be listened to more, a new report has claimed.
The health service ombudsman, Ann Abraham, conducted the study, which looked at 15,579 complaints made about the NHS in England in 2009/10.
Patients unhappy with the response they receive when they complain to an NHS trust can take the matter to the "next step" and report it to the ombudsman.
Ms Abraham discovered that trusts often give a poor or incomplete explanation when people criticise the handling of their care.
The figures, which are not comparable with last year due to changes in the way complaints are assessed, showed that 17% of patients complained about the care offered to them by GPs, 56% of which were upheld or partly upheld.
Of the 659 complaints made about dentists, 80% were upheld or partly upheld.
Hospital, specialist and teaching trusts received 6,304 complaints, or 44% of the total amount.
Overall, 63% of all complaints investigated and reported on by the ombudsman were upheld or partly upheld.
Ms Abraham said: "Many of the lessons that can be learnt from complaints are straightforward and cost little or nothing to implement at local level: a commitment to apologising when things go wrong; clear and prompt explanations of what has happened; improved record keeping and better information for patients about how to complain."
"NHS staff should not be afraid of informing patients and relatives when things have gone wrong. Often patients and relatives can help us to understand what happened and what needs to be done differently to minimise the risk of the same mistake happening again" - Avril Devaney, North Wales
"I think that it is really important that when anything goes wrong in the NHS it is of vital importance that relatives are informed. Where mistakes can be rectified then relatives and staff will need the support of each other to move forward. Where a mistake has resulted in someone's death, relatives must be told, as I believe that it will help in the grieving process. Hopefully, staff will learn from mistakes, no matter how small it may seem" - Kereen Browne, London