Patients with severe hypokalemia or inability to eat need intravenous potassium chloride supplementation. Both hyperkalemia and hypokalemia can cause severe cardiac arrhythmias and even cardiac arrest, and special attention should be paid to the rate and concentration of the infusion when replenishing potassium chloride intravenously. The general principle of rehydration is to add 3 grams of potassium chloride per 1000 ml of sodium chloride or glucose fluid, 1.5 grams of potassium chloride in 500 ml of sodium chloride, and 0.75 grams of potassium chloride in 250 ml of sodium chloride. The rate of infusion should not be too fast, and potassium chloride fluid can cause irritation to the blood vessels. It is manifested as pain in the blood vessels during infusion, and it will also manifest as stomach discomfort, nausea and vomiting. It is important to pay attention to the concentration and speed of potassium chloride infusion.