Fluid therapy is important in the treatment of many medical conditions in medicine. Normal cellular function can be impaired without water and potentially lead to patient death. Therefore, the veterinarian should have extensive knowledge of fluid therapy. Fluid therapy in clinical medicine is used to fulfill the following objectives: (1) to replace dehydration deficits, (2) to maintain normal hydration, (3) to replace essential electrolytes and nutrients, and (4) to serve as a vehicle for the infusions of certain intravenous medications. A fluid therapy plan should be individualized for each small animal patient and constantly re -evaluated and reformulated according to changes in status. The aims of this speech are to help the small animal clinician determine the therapy goals, selecting appropriate fluids and rates of administration, and assessing patient response to the treatment.