PIP: This is a detailed account and comparison of use of 3 types of home-prepared oral rehydration solution versus no early treatment in 4 Thai villages from March 1983 to February 1984. The solutions, prepared with boiling water in a standard 750 ml fish sauce bottle contained: 2 spoons sugar and 2 spoon handle tips salt; 2 spoons sugar and 2 spoon tips tea; or 2 spoon tips salt in rice water as opposed to boiling water. Amounts dispensed were specified by number of watery stools and age of sufferer. All treatment was followed by breast feeding or soft diet within 2-4 hours. There were 0.05 episodes of diarrhea per person yearly, 0.10 per child, 9.5% in infants under 1 year, and 20.1% per child aged 1-4. Recovery rates ranged from 91-99% with home treatment, the highest with the tea mixture. Acceptability was good except for the rice water mixture: rice water is used for pig and dog food in this culture. In the test villages, 6.6% of diarrhea episodes required rehydration at the health center, while the control village needed treatment for 25.9% of episodes at the local health center, provincial hospital or private clinics. The estimated cost of therapy for each diarrheal episode was over $2.00 US for purchased medication, or 30 times the expense of home mixed solution. Medicines used were oral rehydration solutions, sulfa, tetracycline, chloramphenicol, kaolin, loperamide, or herbs. Analysis of some home mixed solutions is reported. The tea mixture contained virtually no electrolytes, but was effective because it was used earlier than solution requiring mealtime rice water, for example. In this trial, where treatment was under control of villagers and fully integrated into the primary health care system, early home treatment was more effective than later care in the center.