“…18 A number of studies used Rome II 20,26,35,37,52,62 or Rome III 45,53,56 criteria for defining functional constipation, implying minimum symptom duration as 12 or 6 months, respectively. Sixteen studies 6,8,14,21,27,[32][33][34]39,41,43,48,49,54,58,60 did not specify the duration of constipation in their patients although one author described it as "a long time" 43 and another "longstanding". 8 The constipation was said to be severe in 11 studies, 18,20,21,27,33,39,41,43,49,53,56 intractable in 9 studies, [8][9][10]16,28,35,45,48,60 severely intractable in 5 studies, 11,…”