Important inroads are being made into understanding the pathophysiology of acute diarrhea. Clear understanding of key mechanisms should suggest new approaches to combat disease. Exciting developments are occurring in terms of super-ORS solutions, particularly with the promise of short-chained glucose polymers and glutamine. Perhaps the most important development is the prospect of a good rotavirus vaccine being available before the end of the decade. Chronic diarrhea seems to be on the increase globally, probably because of the success of ORS. The mechanisms that lead to mucosal injury are elusive and therapy is still largely supportive and empiric. Celiac disease continues to be a puzzle, not least because of the uncomfortable feeling that a majority of cases may be being missed because of atypical presentations. The successful use of long-term parenteral nutrition has allowed survival and better characterization of cases that otherwise would have perished as "lethal protracted diarrhea". Microvillus inclusion disease may be the most common congenital secretory diarrhea. The role of the recently reported high prevalence of glucoamylase deficiency may be important. Lastly attention to micronutrients, particularly low vitamin A and probably zinc, may prove to be important in prevention and amelioration of diarrhea and growth failure.