Bad breath has sooooo much to do with BOTH diet and constipation. Both of these issues need to be addressed in order to correct his breath. Make sure he eats plenty of spinach EVERY day and also buy some green beans to help correct the problem for him to eat every day. Also he should drink half his weight in ounces of water every day. For example, if he weighs 40 pounds, he should drink 20 ounces of water every day and that's every day. He should stay away from ALL sugar, bread, and if he can...any meat. If he absolutely HAS to eat meat, only a little and only white meat that is boiled or broiled. Fried foods are bad for the breath and also EVERY dairy like milk, cheese, etc. Try this strict diet for 2 weeks and see if you see any improvement. God Bless and I hope this helps your little one. Bless you and good luck in your efforts.