To evaluate the safety and efficacy of extended use of polyethyleneglycol3350 laxative as compared to placebo in constipated patients.

Inclusion Criteria:

• Male or female outpatients at least 18 years of age
• Constipated according to ROME I criteria
• On average, fewer than 3 satisfactory BMs per week during the observation period
• 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 corn or polyethylene glycol.

• 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

• Patients that have undergone a colonoscopy within 30 days of beginning the 14 day observation period.

• Patients that are currently taking, or have previously been treated with polyethyleneglycol3350