One of the problems with coin batteries is that their small size makes them easy for children and pets to swallow. Once ingested, the child or pet may experience internal harm from electrical currents, physical pressure on sensitive tissues, and leaking chemicals from the battery. To help prevent this, some manufacturers have given the batteries a bitter flavor that discourages children and pets from putting the batteries in their mouths. However, it’s advised to keep coin batteries out of reach of small kids and pets to avoid a trip to the hospital or vet clinic.