A catheter is a thin tube made from medical grade materials serving a broad range of functions.

Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. By modifying the material or adjusting the way catheters are manufactured, it is possible to tailor catheters for gastrointestinal applications.

Catheters can be inserted into a body cavity, duct, or vessel. Functionally, they allow drainage, administration of fluids or gases, access by surgical instruments, and also perform a wide variety of other tasks depending on the type of catheter. The process of inserting a catheter is catheterization. In most uses, catheter is a thin, flexible tube (“soft” catheter) though catheters are available in varying levels of stiffness depending on the application. A catheter left inside the body, either temporarily or permanently, may be referred to as an indwelling catheter. A permanently inserted catheter may be referred to as a permcath (originally a trademark