Tobacco Smoke Enemas (1750s – 1810s) were used to infuse tobacco smoke into a patient's rectum for various medical purposes, primarily resuscitation of drowning victims. A rectal tube inserted into the anus was connected to a fumigator and bellows that forced the smoke towards the rectum. The warmth of the smoke was thought to promote respiration.
From which we get the term, "Blowing smoke up one's butt."