Body fluid is the general term for the large amount of water contained in the body and the various substances contained in the water. The components of body fluids are water, various inorganic salts (sodium, potassium, chloride, calcium, magnesium and bicarbonate), essential cellular nutrients (sugar, amino acids, fatty acids, etc.), oxygen, carbon dioxide and cellular metabolites. Body fluids are distributed in the intracellular and extracellular, i.e. intracellular and extracellular fluids. Extracellular fluid typically accounts for 20% of body weight, and intracellular fluid can account for up to 40% of body weight. Gastrointestinal diseases, burns, trauma, surgical infections, major surgeries, etc. may lead to imbalance of body fluids, resulting in various symptoms such as thirst, irritability, fatigue, poor appetite, abdominal distension, panic, and altered state of mind. If discomfort occurs, active treatment under medical supervision is recommended.