Button disc batteries are found in watches, cameras, calculators, hearing aids, and computer games. They are easily swallowed by children. These batteries, which contain corrosive fluids, can come apart when swallowed and quickly damage tissue. Some batteries contain potentially life-threatening amounts of mercury.
A disc battery can cause burning, corrosion, or complete destruction of tissue in the upper digestive tract when swallowed. Damage can occur rapidly and is likely to be worse if the battery lodges in the esophagus instead of moving into the stomach. Battery fluid can eat through the lining of the stomach, causing pain and tenderness in the belly, nausea, and fever.
If you think someone has swallowed a disc battery:
Magnets are often found in toys and magnetic play sets. Magnets can be easily swallowed. They can stick to the bowel and cause a blockage or a hole to form. If more than one magnet is swallowed, they could stack together or magnetically join across loops of the intestines and cause serious problems.
Swallowing a magnet may cause symptoms similar to other abdominal problems, such as feeling sick to the stomach (nausea), vomiting, belly pain, or diarrhea.
If you think someone has swallowed a magnet:
WebMD Medical Reference from Healthwise