Over 1,000 care home residents in England and Wales died of thirst or severe dehydration over the past ten years.
Dehydration was noted on 1,158 death certificated between 2003 and 2013 as either the main cause of death or a factor.
More than 300 care home residents died from starvation or when severely malnourished over the same time period. At least 2,814 deaths were related to bed sores.
The figures, revealed by the Daily Telegraph, showed that more people died while dehydrated last year than in 2010, but the number was lower than thwe 2006 peak.
Dr Alison Cook, director of external affairs at the Alzheimer's Society, said: "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."
Norman Lamb, the care and support minister, told the Telegraph that deaths from thirst and starvation were “entirely unacceptable”.
He added that new Care Quality Commission rules would allow the regulator to intervene more effectively, and ministers would act to make company directors personally responsible for the care their organisation provides.