Inclusion Criteria

• Patient weighs at least 18 kg (39.7 lbs) Patient meets Rome III criteria for child/adolescent IBS: at least once per week for at least 2 months before Screening Visit, the patient experienced abdominal discomfort (an uncomfortable sensation not described as pain) or pain associated with 2 or more of the following at least 25% of the time: a) Improvement with defecation b) Onset associated with a change in frequency of stool c) Onset associated with a change in form (appearance) of stool Patient meets modified Rome III criteria for child/adolescent Functional Constipation (FC): For at least 2 months before the Screening Visit, the patient has had 2 or fewer defecations (with each defecation occurring in the absence of any laxative, suppository, or enema use during the preceding 24 hours) in the toilet per week. In addition, at least once per week, patient meets 1 or more of the following: a) History of retentive posturing or excessive volitional stool retention b) History of painful or hard bowel movements (BMs) c) Presence of a large fecal mass in the rectum d) History of large diameter stools that may obstruct the toilet Patient is willing to discontinue any laxatives used before the Pretreatment Visit in favor of the protocol-permitted rescue medicine Patient has an average of fewer than 3 spontaneous BMs (SBMs) per week during the 14 days before the randomization day and up to the randomization. An SBM is defined as a BM that occurs in the absence of laxative, enema, or suppository use on the calendar day of the BM or the calendar day before the BM Patient or parent/guardian/LAR or caregiver is compliant with eDiary by completing both the morning and evening assessments for 10 out of the 14 days immediately preceding the Randomization Visit

Exclusion Criteria

• Patient reports having more than 1 loose, mushy stool (eDiary-recorded stool consistency of 6 on the Pediatric Bristol Stool Form Scale [p-BSFS]) or any watery stool (eDiary-recorded stool consistency of 7 on the p-BSFS) with any SBM that occurred in the absence of laxative use on the calendar day of the BM or the calendar day before the BM during the 14 days before the randomization day and up to the randomization Select medical history or conditions that may be related to other causes of constipation or may interfere with safety and efficacy analyses Patient has required manual disimpaction anytime prior to randomization or disimpaction during in-patient hospitalization within one year prior to randomization Patient is unable to tolerate the placebo during the Screening Period

Want to participate?