Many patients in the terminal phase of their illness experience reduced oral intake before death, due to causes related to their cancer or its treatment. When oral intake is not adequate, dehydration and malnutrition are the obvious results. But these terminally ill patients present a challenge to healthcare providers: to rehydrate these patients or not and, if so, how? Adequate hydration levels are much lower in terminal patients with cancer than in normal adults. Healthcare professionals should assess the patient's hydration needs through personal history, physical examination, and laboratory evaluation before considering the advantages and disadvantages of rehydration, as well as the wishes of the patient and his or her family. In doubtful cases, a short trial of hydration may be appropriate. If hydration is considered, there are a number of methods to consider based on the needs of the patient, including intravenous administration, hypodermoclysis, and proctoclysis. The subcutaneous route is an excellent alternative due to its simplicity, low cost, and feasibility in the home setting.