To present an unusual case of inappropriate antidiuretic hormone secretion syndrome after a minor surgical procedure in a healthy patient.A 71-yr-old woman underwent uneventful laparoscopic cholecystectomy for gallstones under general anaesthesia. Fifty-two hours post operatively she began convulsing and was found to have a serum sodium concentration as low as 112 mmol.L-1. Serum osmolality, urinary sodium concentration and urine osmolality suggested a diagnosis of inappropriate antidiuretic hormone secretion. Subsequent treatment with anticonvulsants followed by strict fluid restriction which increased serum sodium concentrations led to rapid recovery.The syndrome of inappropriate ADH secretion has several well documented causes including major surgery. Few episodes have been described following minor surgery in healthy patients and the only possible risk factor evident in this patient could be her advancing years.