1, there is something wrong with the large intestine. There is inflammation in the intestine. 2, there are many sweat glands, and bacteria are easy to stay here. When sweating, sweat accumulates here and is decomposed by bacteria, which naturally produces an unpleasant smell. There is mud in the belly button. -Add a proper amount of salt to clean boiled water, then soak the cotton into the solution and put it in the navel for 2 minutes to soften the dirt slowly, and then gently scrub it. This will not damage the mucosa and there will be no infection. Or drop a little olive oil or baby oil into it, warm it and dry it with a cotton swab.
Children need to be washed with baby oil. If there is abnormal secretion, seek medical attention immediately.