Ingestion of button batteries by young children is well-reported. Uncommonly, impaction of the battery in the oesophagus may be associated with a oesophagitis, oesophageal perforation and mediastinitis, which may be fatal. Toxicity from leakage of battery contents has not been widely reported. We present first case of accidental lithium poisoning secondary to button battery impaction in the cervical oesophagus. Lithium poisoning should be considered in any child with neurological symptoms following lithium-ion battery ingestion.