Surgery describes any medical procedure where cutting of the skin is involved, but excludes procedures where only a needle pierces the skin, such as an injection or the extraction of blood. Under the laws of most U.S. states and Canadian provinces, only medical doctors may perform surgery on a patient. Surgical procedures range from the routine, such as lancing an abcess, to the extremely specialized such as open heart surgery. Surgery in and of itself is a recognized medical specialty and requires doctors with extraordinary manual dexterity as well as a knowledge of anatomy. However, House and his team often undertake minor surgical procedures themselves.

Surgery usually has to be performed under a general anasthetic, even when the duration of the surgery will be no more than several seconds. There have been cases on House M.D. where surgery was considered without an anasthetic, but in all such cases it was clear that the patient risked death from shock as a result of the procedure.

Surgery is usually performed to correct an anatomical defect or to remove a diseased part of the body. However, on occasion, it can be used for diagnostic purposes. Examples of such surgery are exploratory surgery and biopsy.