On a world-wide basis, 84 cases of CPH were found, 59 females and 25 males: i.e., a F:M ratio of 2.36. Forty-nine cases never exhibited a remitting stage, whereas in 35 cases a history of a remitting stage was obtained, 17 cases still remaining in the remitting stage. In other words, the ratio between the chronic and the remitting stage as of today is 67:17 = 3.94. Accordingly, there seems to be a reverse relationship of the chronic versus the remitting stage, when compared to cluster headache. A maximum attack frequency even of 5-6 attacks per 24 hours seems to be consistent with a diagnosis of CPH. Nocturnal attacks occurred in 55 out of 58 cases where such information was available. An unchanging unilaterality was the rule, in that only 3 exceptions have been reported.