Persistent hiccup is defined as duration lasting longer than 48 hours. Reflex arc of hiccup is divided into three parts : afferent, central, efferent. Afferent portion of the neural pathway of hiccup formation is composed of vagus nerve, phrenic nerve, and sympathetic chain arising from T6 to T12. Efferent limb is phrenic nerve. Hiccup center is located in brain stem, midbrain, reticular system and hypothalamus. Persistent hiccup is very difficult to treat by conventional methods. We performed cervical epidural block of the phrenic nerve root for three patients suffering from persistent hiccup. The therapeutic effect was perfect. The mechanism of the cervical epidural block is not yet defined however it is thought to block the efferent nerve fibers and suppress the reflex arc of hiccup. We conclude cervical epidural block is relatively safe and very effective for treating persistent hiccup.