Toddlers and babies put everything in their mouthsit's how they explore the world around them. Fortunately, 80-90% of the items kids swallow pass through the digestive system without any problems.

Still, two items you should be concerned about are button batteries and pennies. Button batteries are small enough to pass easily down the throat, but then they can get caught in the esophagus or stuck somewhere else in the digestive tract and can burn a hole in the lining within hours. If your child swallows a battery, go to the emergency room immediately.

Pennies made after 1982 contain highly corrosive zinc, and if one gets lodged in the esophagus, the lining may become irritated or damaged. If you notice any of these red flags, take action:

If he has trouble breathing, speaking, swallowing, or crying, do the Heimlich maneuver

If his breathing is labored, if there's excessive drooling, gagging, or vomiting, or if he has a severe stomachache, call 911 or go to the E.R. immediately

If your child doesn't exhibit these behaviors, you can take him to the doctor the next day. The doctor can then can do an x-ray to determine the exact location of the swallowed item. At this point, the doctor may be able to determine whether the penny will need to be removed by a surgeon.

Occasionally, watchful waiting is in order. If the object is not found in the child's stool, then a repeat x-ray is usually done on about the fourth or fifth day after ingestion. If the penny is still in the stomach, then it usually is removed so that it doesn't cause ulceration in the stomach.