We report 18 cases of chronic hiccup (defined as lasting for more than 48 hours) in adults. Among the numerous possible causes, reflux esophagitis proved to be by far the most frequent (50% of the cases). However, hiccup often initiated a self-perpetuating vicious circle. This is possibly because hiccup per se can give esophageal dyskinesia, which in turn leads to gastro-esophageal reflux. The treatment was difficult and whenever possible has been directed chiefly towards the cause. However hiccup remained intractable in many cases even after a possible cause had been adequately cured (e.g., successful Nissen procedure in reflux cases). Central nervous system depressants and myorelaxing drugs were not very helpful, except for baclofen (initial response rate = 60%).