Argon plasma coagulation (APC) is an endoscopic procedure that serves to control bleeding in any lesion located in the gastrointestinal tract. It also helps reduce the size of tumors that are not suited to have surgery on them. APC involves the use of an ionized argon gas jet (plasma) directed through a probe that is passed through the endoscope. The probe is placed at a distance from the bleeding lesion, and argon gas is emitted via the probe. Then it is ionized by a high-voltage discharge. High-frequency electric current is then passed through the jet of gas that results in coagulation of the bleeding lesion.