This study investigated the relationship between symptoms and dehydration in 82 subjects with malignant disease. Assessment of respiratory tract secretions, thirst, and dry mouth were made during the dying phase, and serum biochemistry was analyzed. Follow-up data were also collected when the patient died. The median time from entry into the study until death was 2 days. All subjects died without artificial fluid therapy. Analysis showed that over 50% of subjects had a serum osmolality of less than 295 mOsm/kg. Contrary to previous anecdotal evidence, no statistically significant relationship was demonstrated between the level of hydration and respiratory tract secretions. Twenty-eight percent of subjects were able to respond to questions; 87% of these had a dry mouth and 83% felt thirsty. No statistically significant association was found between level of hydration and these symptoms. Artificial hydration to alleviate these symptoms in the dying patient may, therefore, be futile. Further work needs to be carried out regarding the cause and treatment of these symptoms in the dying patient.