The stomach bug ends in 48 hours. The aftershocks can run for weeks. About 1 in 10 children who catch a viral gastroenteritis spend the next month or two with alternating loose stools and hard, infrequent stools, a vague anxiety before bowel movements, and a parent quietly worrying about weight and growth. This is the story of post-infectious gut recovery in kids — the chemistry of what actually broke, the Monte Carlo evidence behind the supplements and dietary moves that actually work, and an honest map of how long this takes to resolve.