Fever episodes in 104 institutionalized patients with Alzheimer's disease were prospectively evaluated to determine the impact of antibiotic treatment on fever outcomes. During the 34-month observation period, 75 patients developed 172 episodes of fever and 29 patients had no fevers. Patients who developed fevers had more advanced disease than patients who did not. Patients who received diagnostic workup of all fevers and treatment with antibiotics (Antibiotic Group) were compared with patients who received comfort measures only (Palliative Group). The incidence of fever was similar in the Antibiotic and Palliative groups. Survival analysis revealed that, for the more severely affected patients, there was no difference in survival between the groups. Among less severely affected patients, survival was higher for the Antibiotic than the Palliative Group. These results suggest that treatment of fever with antibiotics does not alter the outcome of fever in patients with advanced Alzheimer's disease.