We report the case of a 4-year-old boy who sustained an oesophageal burn grade II-III due to ingestion of an alkaline substance from a leaking cylindric 3.3 cm diameter battery, by putting the battery to his mouth and sucking the caustic solution. Lye ingestion by sucking a big cylindrical alkaline battery has not yet been reported in the medical literature. We recommend the production of safer alkaline battery cover tubes in order to eliminate any possibility of leakage. Accidents like this might occur more often, since battery collecting and recycling is becoming more common.