A: Baby gas comes from two sources: Swallowing air during feeding and crying, and during the course of digestion, as harmless bacteria break down undigested sugars in the large intestine. Some breastfed babies may produce excessive gas when their mothers eat gas-triggering vegetables, such as broccoli, cauliflower, cabbage, Brussels sprouts, beans, and onions. (If you're eating these foods and notice your baby is gassy, you may want to limit them in your diet.) Feeding babies too much fruit juice can also cause gas, as well as bloating, tummy pain, and diarrhea. Don't give juice to babies under 6 months, and limit juice intake to 4 to 6 ounces a day for babies over 6 months.
Originally published in American Baby magazine, August 2005. Updated 2009.