• Safety (Adverse events and laboratory testing)
  

• Assessment of constipation using ROME I criteria and analysis of individual ROME I criteria
  

Inclusion Criteria:

• Inclusion Criteria:
• Male or female outpatients at least 18 years of age
• Constipated according to ROME I criteria
• If female and of childbearing potential, patient must be surgically sterilized or using oral contraceptives, depot contraceptives, intrauterine device, or testifies that she is monogamous with a vasectomized partner, or practices abstinence and will continue to do so during the duration of study
• Are otherwise in good health, as judged by a physical examination
• In the investigator’s judgment, patient is mentally competent to sign an instrument of informed consent

Exclusion Criteria:

• Patients with heme positive stool at screening. Patients with heme positive stool that can be attributed to hemorrhoids or anal fissures are eligible for inclusion.
• Patients with hypo- or hyperthyroidism as determined by history, or screening TSH results.
• Patients with known or suspected perforation or obstruction.
• History of gastric retention, inflammatory bowel disease, bowel resection, or colostomy.
• Patients with a known history of organic cause for their constipation.
• Patients meeting the ROME definition of Irritable Bowel Syndrome

• Patients currently taking any of the following medications that are known to effect bowel habits:

  • Antidiarrheals
  • Antacids containing magnesium or aluminum salts
  • Anticholinergics
  • Antispasmodic agents
  • Erythromycin and other macrolides
  • Octreotide
  • Lotronex, Zofran, or other 5-HT3 antagonists
  • Zelnorm, or other 5-HT4 agonists
  • Opiods/narcotic analgesics
  • Prokinetics
  • Serotonin re-uptake inhibitors or tricyclic antidepressants
  • Calcium antagonists
• Patients who are breastfeeding, pregnant, or intend to become pregnant during the study.
• Female patients of childbearing potential who refuse a pregnancy test.
• Patients with a known allergy to polyethyleneglycol.
• Patients who, in the opinion of the investigator, should not be included in the study for any reason, including inability to follow study procedures.
• Patients who, within the past 30 days have participated in an investigational clinical study