Clinical Research Directory

Inclusion criteria: * Able to communicate adequately with the investigator and to comply with the requirements for the entire study * Meet Rome III criteria for functional constipation as assessed by questionnaires in period 1, i.e., report at least 2 of the following symptoms for last 3 months or more with symptom onset at least 6 months prior to diagnosis: a) \<3 SBMs/week b) hard or lumpy stools ≥ 25% of time c) straining ≥ 25% of time d) sense of incomplete evacuation ≥ 25% of time e) feeling of anorectal blockage ≥ 25% of time or f) manual maneuvers to facilitate defecation ≥ 25% of time. Patients who meet Rome III criteria for irritable bowel syndrome will also be eligible provided they also meet above criteria. Exclusion criteria: * Current use of opioid analgesics. Patients on opioids will be allowed to participate if they have discontinued them for at least 3 days (72 hrs.) before date of screening and are willing to stay off them for the duration of the study. * Current use of anticholinergics (e.g. nortriptyline, amitriptyline, hyoscyamine). Patients who use low dose tricyclic antidepressants (nortriptyline upto 50 mg/day or amitriptyline upto 25 mg/day ) will be eligible provided they do not increase the dose during the study period. Patients on higher doses or on other anticholinergics are eligible to participate if they can discontinue their medication at least 3 days (72 hrs) before the date of screening and are willing to stay off them till the study is complete. * Current use of laxatives (MiraLax, Ex-lax, senna, herbal supplements), linaclotide, lubiprostone, and prucalopride to treat constipation- patients using these medications will be eligible to participate if they can discontinue the medication at least 3 days (72 hrs.) before the date of screening and are willing to stay off them till the study is complete.