context: Most babies spit up sometimes, even several times a day. But when vomiting causes other problems or comes with other symptoms, it may be due to acid reflux, also called gastroesophageal reflux disease ( GERD). GERD may seem like an adults-only issue, but it can happen to infants and children, too. The most common symptoms in kids are: Vomiting often A cough that won't go away Refusing to eat or trouble eating (a child may choke or gag) Crying during or after a feeding Heartburn, gas, or belly pain Acid reflux happens when food and acid in the stomach move back up into the tube that goes to the mouth, called the esophagus. Sometimes it moves into or out of the mouth. Most infants with the condition are healthy -- it's just that parts of their digestive systems aren't fully mature yet. They usually grow out of GERD by the time they are 1 year old. In older children, the causes of GERD are different than for infants and adults. In many cases, it happens when the muscular valve between the stomach and esophagus relaxes or when pressure builds up below that valve. Usually, the doctor can diagnose acid reflux based on the symptoms you describe and your child's medical history, especially if the problem happens regularly and causes discomfort. Sometimes, your child may need more tests, such as: Barium swallow or upper GI series. This is a special X-ray test. Your child will drink a chalky substance to highlight his esophagus, stomach, and upper part of his small intestine. It can show if anything is blocking or narrowing these areas. p H probe. Your child will swallow a long, thin tube with a probe at the tip, which will stay in his esophagus for 24 hours. The tip measures levels of acids in his stomach. If your child has breathing problems, this test also can help the doctor tell if they're the result of reflux. Upper GI endoscopy. This test uses a thin, flexible, lighted tube and camera that allows the doctor to look directly inside the esophagus, stomach, and upper part of the small intestine. Gastric emptying study. Your child drinks milk or eats food mixed with a radioactive chemical, and a special camera follows it through his digestive tract. It will show if his reflux happens because his stomach empties too slowly. You can try a few lifestyle changes to help a child with acid reflux: For infants: Raise the head of the baby's crib or bassinet Hold him upright for 30 minutes after a feeding Thicken his bottle feedings with cereal (ask your doctor before you try this) Change his feeding schedule Try giving him solid food (with your doctor's OK) For an older child: Raise the head of his bed Keep him upright for at least 2 hours after he eats Serve him several small meals throughout the day rather than three large ones Limit any foods and drinks that seem to make his reflux worse Encourage him to get regular exercise If the reflux is severe or doesn't get better, your doctor may recommend medication to treat it. Medicines to help with gas include: Simethicone Calcium carbonate antacid He might also prescribe a medicine to help your child's stomach make less acid. But researchers aren't sure whether these drugs ease reflux in infants. For the most part, antacids and gas-fighting drugs are safe. At high doses, antacids can cause some side effects, such as diarrhea. If your child takes high doses of them for a long time, he might have a higher risk of thinning bones, called rickets, or vitamin B12 deficiency. Most children don't need surgery to treat reflux. But it can help those who've tried other treatment that hasn't worked or kids who have breathing problems, pneumonia, or other serious problems from GERD. In the most common type of surgery, a surgeon wraps the top part of the stomach around the esophagus, forming a cuff that closes off the esophagus whenever the stomach squeezes -- preventing reflux. Like any operation, there are some risks to this surgery. Talk about them with your child's doctor. She can help you decide if it's the right treatment for your child.