For reasons of compassion and environmental conservation, a vegetarian diet is suggested, but not required, for Tzu Chi Commissioners. This population of Commissioners is a non-smoking, non-drinking population, with a wide range of dietary practice: about 30% are vegetarians, 38% partial vegetarians, and 32% omnivores. A free comprehensive health examination is available for Tzu Chi commissioners at Tzu Chi hospitals every two years. TCHS was established at Dalin Tzu Chi Hospital, where both Commissioners and patients coming for health examinations have been invited to participate in the study.