Participants will be recruited either through clinics at the functional gut clinic or through interest shown to advertising for the study. If the patient is deemed eligible they will be given atleast 24 hours to review the patient information sheet. If they would like to proceed with participation they will be given the chance to ask the study team any questions. If they would still like to proceed the participant will be asked to sign three copies of the informed consent form.~The participants will be required to visit the clinic twice during the study. The day before visit 1 the patient will be required to follow a low residue diet as part of preparation for the hydrogen methane breath. On the day of the first visit participants will complete a hydrogen methane breath test as per the functional gut clinics test protocol, the patient will also be asked to fill two questionnaires about their symptoms. Participants will then be provided with a 10 day bowel and symptom diary and a 10 day supply of blinded the intestinal adsorbent . Participants will be provided with instructions on how to take the the study product and training on completing their daily diary. They will be required to take the study product for 10 consecutive days according to manufacturers instructions.~Participants will return for the second and final visit on the final day of consuming the study product. The day before visit 2 the patient will be required to follow a low residue diet as part of preparation for the hydrogen methane breath. On the day of the second visit participants will complete a hydrogen methane breath test as per the functional gut clinics test protocol, the patient will also be asked to fill two questionnaires about their symptoms. Once these study procedures are complete the participants will have finished their participation in the study.
To determine the effect of an intestinal adsorbent on hydrogen and methane breath levels in patients who have been on long term PPI therapy reporting reflux and abdominal symptoms at baseline.