Withholding and Withdrawal of Potentially Life-sustaining Treatment
… That there is a right to choose how one’s body will be dealt with, even in the context of beneficial medical treatment, has long been recognized by the common law. To impose medical treatment on one who refuses constitutes battery, and our common law has recognized the right to demand that medical treatment which would extend life be withheld or withdrawn.
Canadian courts have recognized a common law right of patients to refuse consent to medical treatment, or to demand that treatment, once commenced, be withdrawn or discontinued (Ciarlariello v. Schacter,  2 S.C.R. 119). This right has been specifically recognized to exist even if the withdrawal from or refusal of treatment may result in death (Nancy B. v. Hotel-Dieu de Quebec (1992), 86 D.L.R. (4th) 385 (Que. S.C.); Malette v. Shulman (1990), 72 O.R. (2d) 417 (C.A.)). …
Whether or not one agrees that the active vs. passive distinction is maintainable, however, the fact remains that under our common law, the physician has no choice but to accept the patient’s instructions to discontinue treatment. To continue to treat the patient when the patient has withdrawn consent to that treatment constitutes battery (Ciarlariello and Nancy B., supra). …
More recently, Justice Smith characterized withholding and withdrawal of potentially life-sustaining treatment as “conventionally ethical end-of-life practice[s]” (at 186) (Carter v Canada (Attorney General), 2012 BCSC 886).