准确的药物剂量是保证疗效、防止毒副反应的关键。在儿科，剂量多以每公斤体重计算，用量偏小，临床不易准确应用而造成药量不足或过量。笔者介绍以下三种计算方法供参考。l常数法以该药物的毫升数除以药量所得的固定数值（即常数），乘以需用的药物剂量，即得应抽吸的毫升数卜 Accurate drug dose is to ensure efficacy, prevent the key to toxic side effects. In pediatrics, the dose of more per kilogram of body weight, the amount of small, difficult to accurately clinical application caused by insufficient or excessive dose. The author introduces the following three calculation methods for reference. l constant method to the number of milliliters of the drug divided by the fixed value of the drug dose (ie, constant), multiplied by the need to use the drug dose, that is, the number of ml