1. those needing acid suppression who are genuinely allergic or intolerant or contraindicated to all PPIs, which is rare;2. those needing acid suppression where low magnesium occurs, which is felt as very rare;3. those who have needed upward titration for reflux symptoms despite high dose PPIs, where addition of H2RA, generally at night time, helps.4. occasionally there seems to be a small number who claim not to do well on PPI yet symptomatically get better on H2RA.