From 600 million to 750 million people are reckoned to be at risk from infection with food-borne trematodes (FBTs) that have a worldwide distribution (WHO, 1995, 2000). Although many species of digenean fluke are involved in zoonotic FBT infections (see Coombs and Crompton, 1991) we have concentrated mainly on the public health significance of seven species (Table 1.1 and Table 7.1). This approach allows the principles that underpin the prevention and control of any FBT infection to be identified. Whether an infection has public health significance or not is not always easy to establish. We consider that public health status applies when health professionals have concluded that measures for the protection and treatment of a community should be implemented. Provision to treat and support individuals suffering from one of the rarer forms of food-borne trematodiasis is equally important, but may not justify a program of public health intervention.