The main factors to maintain the water balance inside and outside the capillary are: plasma colloid osmotic pressure, capillary hydrostatic pressure, capillary permeability. 1. Plasma colloid osmotic pressure: plasma colloid osmotic pressure is mainly composed of albumin, when the body of albumin decreases, such as liver disease, renal disease, will cause an imbalance between the internal and external water balance of the capillaries, the capillary fluid leakage of tissues, and the body appears to be swollen. 2. Capillary hydrostatic pressure: when some diseases lead to increased pressure in the capillaries, such as hypertension, lymphatic reflux obstruction, which leads to increased pressure in the capillaries, intravascular fluid will be transferred to the tissues, and tissue edema occurs. 3. Capillary permeability: when there is an allergic substance producing histamine, inflammatory mediators produced by infection, endothelial cell damage, etc., there can be an increase in the permeability of the capillaries, and there is an intravascular fluid flow to the outside of the blood vessels. If any of the above situations, it is recommended to go to the hospital for consultation in order to avoid delays.