The main reasons why 3-year-old babies’ lower body smells bad are: poor hygiene, inflammation, rashes and so on. 1. Poor hygiene: 3-year-old babies do not pay attention to the care of the vulvar area, urine or feces accumulated in the vulvar area, if not cleaned up in a timely manner, it will emit a relatively unpleasant odor. Usually must pay attention to the baby’s vulvar part of the clean, diligent cleaning, diligent change underwear. 2. Inflammation: female baby vulva or vagina infection, because vulva, vagina inflammation, will lead to increased secretion, and odor; male baby vulva infection, will lead to glans, urethra will have abnormal secretion, accompanied by odor, which leads to the lower body has a bad smell. 3. Rash: baby vulvar skin allergies lead to the production of rashes, if you do not pay attention to care, the rash will break, or even ulceration, inflammation, abnormal secretions, the baby’s lower body will appear a bad smell. 3-year-old baby’s lower body appeared to smell bad, such as improving hygiene habits are still not relieved, we should promptly seek medical attention, so as not to bring harm to the baby’s physical health.