Recurrent abdominal pain (RAP) is the most common type of pain in school age children and young adolescents. Previous studies suggest that stress plays an important role in the activation of specific cells that can produce pain within the stomach and intestines. Medication is the standard approach to the treatment of RAP in children. Although medication is helpful for many children, medication alone is not always enough. Biofeedback trains individuals to use relaxation strategies effectively to relieve emotional and physical symptoms, and has been used successfully for stress and pain reduction with both children and adults. It has shown promising results when used alone in the treatment of children with RAP. Research is needed, however, to determine whether biofeedback training is helpful when used in conjunction with medication. Information about how biofeedback training affects the central nervous system and the cells that produce pain also would be useful in refining treatments for this large group of children. The current research will be done in three steps, with Phase 1 designed to evaluate the time, resources, technical support, and sample size needed for successful completion of the full research study. Twenty children (ages 8-18) with eosinophilic duodenitis, a specific form of RAP, will be enrolled and randomly assigned to one of two groups: 1) Standard of Care; or 2) Biofeedback (standard medical care plus 10 sessions of biofeedback training). Measures of pain, functional disability, quality of life, physiological arousal, and global treatment response will be collected pre- and post-intervention, as well as 3 and 6 months later. Data collected will be used to determine how many participants will be needed for the full research study. If biofeedback training is ultimately found to be a positive addition to standard medical treatment, this could lead to improved health outcomes for children with RAP. This information also could result in greater treatment efficiency and reduced health care costs for families, insurance providers, and the hospital system.