Our expert says:
Bad breath can come from tooth decay, chronic post nasal drip, lung conditions like bronchitis or even from acid reflux from the stomach. See http://www.health24.com/medical/Condition_centres/777-792-3000-3459,12537.asp
Your little boy may get Breath holding spells and it is quite common in young children - it is usually an emotional reaction. However you should let your doctor check that there are no medical causes for this like anemia or epilepsy. The best way to prevent this is to try and distract him as soon as possible when he starts crying.
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