The Diarrhea Study Group was established in 1981 under the leadership of Dr. Mediadora Saniel. In 1993, the study group leadership was transferred to Dr. Cecilia Acuin and in 1995 to Dr. Celia Carlos, the current study group leader. For the past 30 years, the study group undertook research projects which addressed various factors which influence diarrheal disease control and prevention. The study group focused on etiology and epidemiology of diarrheal diseases, diagnosis, case management, prevention and program evaluation issues. From 2005 onwards, the study group started focusing on studies to define the disease and economic burden of rotavirus gastroenteritis and economic evaluation of rotavirus vaccine in the Philippines, rotavirus being the most common etiologic agent of acute diarrhea in children.