Septic edema is a type of tissue swelling caused by the accumulation of excessive interstitial fluid containing relatively little protein, which is soft when pressed with the hand and can sink significantly. The main reason for its appearance is the presence of interstitial fluid in the tissue spaces caused by various diseases that prevent the filtration of interstitial fluid from the small arterial end from being completely reabsorbed via the small venous end. It is usually divided into generalized edema and localized edema. Systemic edema is mainly seen in heart failure, constrictive pericarditis, nephritis, nephrotic syndrome, liver cirrhosis, and other diseases. Localized edema can be seen in inflammatory edema caused by localized cellulitis, lymphatic reflux obstructive edema caused by lymph node dissection, and venous reflux obstructive edema caused by venous thrombosis in the lower extremities.