We investigated the antecedents of ingestion of dishwashing machine detergent to enable the development of effective countermeasures. Parents who had sought advice from the Victorian Poisons Information Centre about dishwasher detergent poisoning exposures of their children were interviewed by telephone. Almost all the children (94 per cent) were aged between 6 and 29 months. Of the 61 children included in the survey, 53 (87 per cent) gained access to the detergent from the dishwasher. Of these, 50 (94 per cent) took the detergent from the dispenser on the internal surface of the door of the machine, and 38 (76 per cent) of these ingested detergent remaining in the dispenser after operation of the machine. Parents were present in the room on 78 per cent of occasions at the time of ingestion. Most parents (72 per cent) were aware of the toxicity of the detergents. Relocation of the dispenser or redesigning it to prevent access both before and after operation would have prevented most of the exposures to detergent. Altering the detergent to prevent caking or sludging might prevent many of the exposures to detergent remaining in the dispenser after operation of the machine. The level of prior knowledge about toxicity suggests that education or additional warnings are unlikely to contribute substantially to prevention of poisoning. Telephone call-back to identified cases is a useful method of investigating complex poisoning problems and developing effective countermeasures.