In the prevention of diarrhoea, health professionals often advocate boiling as a method of choice to provide safe household drinking-water to villagers in the less developed countries. We have examined the financial feasibility of this recommendation in a village study in Bangladesh. Family income was categorized and the pattern of household fuel consumption was determined. Families in the lowest income quartile would have to spend approximately 22% of their yearly income on fuel, and those in the highest income bracket approximately 10%. Boiling of drinking-water would result in an 11% increase in the household budget (as a percentage of income) for a typical family in the lowest income quartile, compared with a 3% increase for a family in the highest income quartile. We conclude that recommendations concerning boiling of drinking-water in developing countries should not be made until their economic feasibility has been demonstrated.