Assess the safety and efficacy of polyethyleneglycol3350 laxative as compared to placebo therapy in pediatric patients with a history of constipation.

Inclusion Criteria:

• Male or female outpatients between the ages of 4 to 16 years.
• Adolescent female patients must not be pregnant or lactating.
• constipated according to ROME I definition
• Two or fewer bowel movements during the initial observation week.
• Absence of a stool impaction
• Bowel movement after receiving enema
• Are otherwise in good health, as judged by a physical examination.
• Parent or guardian is mentally competent to sign an instrument of informed consent

Exclusion Criteria:

• Patients with heme positive stool at baseline exam.
• Patients with fecal impaction at baseline, or after the observation period, as indicated by physical exam
• Patients with known or suspected perforation or obstruction other than fecal impaction.
• 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 history of organic cause for their constipation.
• Patients with congenital malformations that produce constipation (Hirschsprung's disease, imperforate anus, children with cerebral palsy or other neurologic abnormalities, or systemic diseases).
• History of gastric retention, inflammatory bowel disease, bowel resection, or colostomy.
• Use of concomitant medications that cause constipation
• 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 with known allergy to polyethyleneglycol or polyethyleneglycol containing medications.
• Patients with clinically significant elevations of TSH or abnormal plasma electrolytes.
• Patients who, within the past 30 days have participated in an investigational clinical study