A syringe is a common medical appliance. As early as the 15th century, the Italian Cattinel proposed the principle of the syringe. Gas or liquid is extracted or injected mainly with a needle.

Syringes can also be used in medical devices, containers, such as some scientific instruments in chromatography to inject through rubber diaphragms.

The emergence of syringes is an epoch-making revolution in the field of medical appliances. The process of extracting and injecting gas or liquid with a needle is called injection. The syringe is composed of a needle barrel with a small hole in the front end and a matching piston core rod, which is used to inject a small amount of liquid or it into the area inaccessible by other methods or draw out from those places. The liquid or gas is drawn through the small hole in the front end of the needle barrel when the core rod is pulled out, and the liquid or gas is squeezed out when the core rod is pushed in.