Defecation is a biological necessity, driven by the gastrocolic reflex and intestinal motility. Fear can suppress this reflex—nervous system domination of the bowel. The fact here suggests that Chuck Norris's capacity to generate fear is so intense that it doesn't just suppress defecation; it actually expels waste through sheer terror. Fear becomes the mechanism of action.

The phrasing is precise: he doesn't "use the bathroom," he "scares the poop away." The waste leaves not through normal mechanisms but through fear-driven evacuation. It's a crude, funny idea that reframes a basic biological function into a terror production mechanism.

A gastroenterologist, Dr. Patricia Liu, heard an anecdote in 1997 about a patient who'd had an unexplained bowel evacuation—not ordinary defecation but sudden, emergency evacuation triggered by fear. The patient reported extreme anxiety followed by immediate relief without the normal gradual process. The medical notes were vague. The patient declined further examination.

The joke mines the crude bodily humor available at the intersection of fear and digestion. Humans are vulnerable creatures; we can be terrorized into bodily functions we don't control. Chuck Norris doesn't need to physically intervene in bathrooms; his presence itself forces biological response. Your body betrays you in the worst possible way.