During 1980-1990 BRAC, a Bangladeshi non-governmental organization, taught over 12 million mothers how to prepare oral rehydration therapy (ORT) at home with lobon (common salt) and gur (unrefined brown sugar). This was followed by a strong promotion and distribution of prepackaged ORS by various agencies including the government. In 1993 we assessed knowledge of ORT preparation, its local availability and its use for the management of diarrhoea. Over 9000 households in 90 villages were revisited; 306 government outreach health workers, 296 drug sellers, and 237 village doctors were interviewed; 152 government facilities and 495 pharmacies/shops were visited. ORT prepared by mothers in a sub-sample of the households was analyzed for chloride content and interviewers collected information on use of ORT for diarrhoeal episodes occurring in the preceding two weeks. The data quality was assessed through a resurvey of sample respondents within two weeks of the first interview. Over 70% of the mothers could prepare a chemically 'safe and effective' ORS. A significant proportion of these mothers were very young at the time of the mass campaigns using house to house teaching, implying an intergenerational transfer of the knowledge on ORT. ORT was found to be used in 60% of all diarrhoeal episodes, but the rate varied with the type of diarrhoea, being highest for daeria (severe watery diarrhoea) and lowest for amasha (dysentery). Drug sellers and village doctors now recommend ORT much more frequently than before. Members of the medical profession (qualified and unqualified) still lag behind in prescribing the use of ORT. The availability of pre-packaged ORS in rural pharmacies has improved enormously. There is convincing evidence that the widescale promotion in the past of ORS for dehydration in diarrhoea has led to this marked improvement today. Nevertheless the use of rice-based ORS, culturally appropriate messages and the promotion of ORS with food offer opportunities to further improve the utilization of ORT.