A total of 84 patients ( 53 female , 31 male ; age range 20-70 years ) with IBS and diarrhea according to Rome-III criteria were randomly allocated to receive one capsule a day for 6 wk containing : ( 1 ) I. 31 high dose ( n = 28 ) ; ( 2 ) I. 31 low dose ( n = 27 ) ; and ( 3 ) placebo ( n = 29 ) .