GSH is also an important component of the epithelial lining fluid of the intestines, helping to keep intestinal mucus thin, serving to defend the intestinal system against reactive oxygen species, and keeping inflammation in check under normal circumstances. GSH is an FDA-approved treatment for AIDS-related cachexia. The growing recognition of GSH system dysfunction in CF, coupled with an established research literature on the role of GSH in gastro-intestinal function and weight gain in non-CF contexts, suggest a new intervention for growth failure in early childhood in CF patients. Specifically, investigators hypothesized that oral glutathione could effectively treat CF growth failure in pediatric patients.