More than 1,000 care home residents in England and Wales died of thirst or while suffering from severe dehydration over the past decade, it was reported.
Figures obtained by the Daily Telegraph showed that 1,158 care home residents suffered dehydration-related deaths from 2003 to 2012.
According to the newspaper dehydration was noted on death certificates as either the main cause of death or a contributory factor.
Some 318 care home residents died from starvation or when severely malnourished over the same period, and 2,815 deaths were related to bed sores.
The data was obtained from the Office of National Statistics under freedom of information laws.
The figures showed that more people died while dehydrated last year than when the coalition came to power in 2010, but the number was lower than the 2006 peak.
Charities warned that an improvement in training for care home staff was necessary to look after patients.
Dr Alison Cook, director of external affairs at the Alzheimer's Society, said: "It makes you sick to the stomach that you are handing your loved ones over with even the remotest possibility they could starve to death or die of thirst.
"There is a real need for better training for those who are looking after elderly and vulnerable people. But even more important is allowing people the time to really care for someone."
In October the health and social care watchdog announced that h idden cameras and ''mystery shoppers'' reporting back on their experience of services could be used as part of measures to prevent abuse and neglect in care homes.
Andrea Sutcliffe, the new chief inspector of adult social care, said there was a need for a ''proper conversation'' about the use of hidden cameras after the move was raised with the Care Quality Commission (CQC).