Why are Americans spending billions on gluten-free products? Is it just a fad or does it make a difference? Perhaps the latter. Several of my patients avoid gluten without any apparent need to do so, and they are convinced their health has improved. One told me that her abdominal bloating, gas and pain have improved. Another says her skin cleared up, and she no longer retains water. Another claims that her brain fog" is gone, and still another believes that her chronic neck pain due to muscle tension has improved significantly. What are they self-treating? None of them has celiac disease [or] a wheat allergy. They suffer from a syndrome that has yet to be clearly defined. The term "non-celiac gluten sensitivity" (NCGS) appears to be gaining traction. NCGS is what we call a "clinical diagnosis," a syndrome defined by symptoms alone, not by tissue biopsy or blood test. What are the symptoms of NCGS? Abdominal pain, eczema and/or rash, headache, "foggy mind," fatigue, diarrhea, depression, extremity numbness and joint pain. There is nothing unique about these symptoms, which occur in many other conditions. Though the small intestine of those with NCGS looks normal, symptoms appear to go away when gluten is removed from the diet and reappear when gluten is reintroduced. Ultimately, a powerful medical group, such as the American Gastroenterological Association, needs to issue criteria by which someone can be said to have gluten sensitivity.