Children may need them to run all those toys under the Christmas tree – but button batteries can be dangerous.
Trading standard and health officers are warning parents to be extra vigilant as the button-shaped batteries look like sweets to a child and are easily swallowed, causing choking and even uncontrollable bleeding and death.
Lithium batteries are found in all sorts of devices, including toys, keyrings, smart phones, cameras and hearing aids.
The main danger is not from what they contain but the electrical charge which can cause serious internal bleeding.
When the battery comes into contact with a liquid, such as saliva, it creates a build-up of sodium hydroxide which is caustic soda, burning a hole in the throat or stomach, even into major blood vessels, or damaging other internal organs.
David Marsh, of Shetland trading standards, said: “Most products containing button cell batteries have a battery compartment cover which is secured with a small screw and are therefore safe for children to use.
“The real problem is when spare batteries are left within a child’s reach, as even a used button cell battery can cause serious injury.”
Susan Laidlaw, public health consultant with NHS Shetland, advised: “Seek medical help immediately if your child has swallowed a button cell battery, as quick action will help to minimise the severity of any injury.”