An 86-year-old gentleman was brought to the emergency department after a massive overdose of slowrelease potassium chloride and indapamide. The initial serum potassium was 6.8 mmol/L. His abdominal X-ray did not reveal any radio-opaque drugs. Whole bowel irrigation was commenced shortly after presentation. There was no rebound of hyperkalaemia and his stay in the acute hospital was short. Slowrelease potassium overdose is uncommonly reported in the medical literature; such poisoning in the elderly has not been reported. Previous case reports are summarised and the management of this uncommon poisoning is discussed. (Hong Kong j.emerg.med. 2007;14:169-173) Case presentationA n 8 6 -ye a r -o l d g e n t l e m a n , w i t h h i s t o r y o f hypertension and regular follow-up in a government outpatient clinic (GOPD), was suspected to have early dementia and was referred to the memory clinic. Currently, he was on indapamide (Natrilix) 2.5 mg daily and slow-release potassium chloride (Slow-K, 600 mg or 8 mmol per tablet) 2 tablets per day. In March 2007, he was followed up three days before attending our department and was given a total of 41 tablets of Natrilix and 82 tablets of Slow-K. One day before attending our department, his daughterin-law found that only a few tablets of the drugs were left. He was brought to the GOPD and was immediately referred to our department. He was estimated to have ingested at least 30 tablets of