Infusion is also called intravenous drip or hanging water. It is a large dose (more than once 100ml) injected into the body by intravenous drip. Usually packed in glass or plastic infusion bottles or bags, without preservatives or bacteriostats. When in use, the dripping speed is adjusted by the infusion set, and the infusion set can continuously and stably enter the vein to supplement body fluids, electrolytes or provide nutrition.