Taken together, the above examples indicate that physiology-based diagnosis has a substantial overlap with symptom-based diagnosis. Neither symptomatic treatment nor therapy aimed at restoring normal physiology has had much success. It is still uncertain if measurement of physiologic parameters facilitates the doctor-patient relationship, whether results are abnormal or normal. However, the addition of physiology parameters to the evaluation of therapeutic interventions aimed at symptom reduction in FGIDs can possibly facilitate the identification of subgroups with a higher probability of treatment success. Unfortunately, our experience from clinical trials in this area is that physiology testing usually disappears as a new drug moves from phase II to phase III trials. In the ideal situation, the development of measurement methods with better availability and standardization, like different ingestible capsules, will help us to merge physiology and symptoms regarding both diagnosis and treatment evaluation.