This is a randomized, double-blind, placebo-controlled study. Subjects between of 5-16 years of age with FAP as defined in the Rome III criteria and with pain severity of at least 40 mm on a 100 mm VAS scale and pain frequency of at least 1 episode per week over the preceding 8 weeks will be recruited. In accordance to the specific Rome III criteria for inclusion, FAP is defined as a variable combination of chronic or recurrent gastrointestinal symptoms not explained by structural or biochemical abnormalities.