The question of whether or not to give intravenous fluids to cancer patients who are in the last stages of their illness is one that has become problematic to health professionals, particularly those working in terminal-care settings. This article attempts to give a better understanding of the subject by unraveling some of the issues involved. The different types of dehydration and the signs and symptoms that may be experienced by dying patients who are dehydrated are defined. Some of the beneficial effects, as well as the ill effects, that such dehydration may cause are delineated. An analysis is made of health professionals' attitudes to dehydration in dying cancer patients and the special ethical problems associated with the question. There is then a practical synthesis of these facts into the formation of guidelines to facilitate the decision-making process related to the initiation of parenteral fluids in dying patients, and a discussion on the law as it pertains to the treatment of dehydration in such patients.