Drinking less water after heart surgery is to avoid aggravating the heart, which may cause adverse reactions. Heart surgery includes congenital heart surgery and acquired heart surgery. Congenital heart surgery includes ventricular septal defect repair, arterial duct ligation, etc. Acquired heart surgery includes valve replacement, coronary artery bypass grafting, and heart valvuloplasty. You need to drink less water after having heart surgery, if you drink too much water it will lead to a heavier burden on the heart and may even cause heart failure. Therefore, in addition to controlling the amount of water intake, the total amount of fluid during infusion should also be controlled. The amount of water intake after cardiac surgery should be determined according to how much the patient sweats, or how much he or she urinates. Patients should follow the doctor’s instructions for treatment, do not blindly treat yourself, so as not to delay the condition or cause adverse reactions.