To compare the safety and efficacy of 2 different bowel cleansing preparations prior to colonoscopy in adult subjects.

The goal of the study is to evaluate the efficacy of 2 different HalfLytely preparations to produce a clinically acceptable degree of cleansing of the bowel, sufficient for colonoscopy.

Inclusion Criteria:

- Male or female outpatients who are undergoing colonoscopy for the following routinely accepted indications:

Evaluation of BE results GI bleeding Anemia of unknown etiology Neoplastic disease surveillance Endosonography Inflammatory bowel disease Unknown diarrhea or constipation etiology Polypectomy Laser therapy Routine Screening

• At least 18 years of age
• Otherwise in good health, as determined by physical exam and medical history
• If female, and of child-bearing potential, is using an acceptable form of birth control (hormonal birth control, IUD, double-barrier method, depot contraceptive, sterilized, abstinent, or vasectomized spouse)
• Negative urine pregnancy test at screening, if applicable
• In the Investigator's judgment, subject is mentally competent to provide informed consent to participate in the study

Exclusion Criteria:

• Subjects with known or suspected ileus, gastrointestinal obstruction, gastric retention, bowel perforation, toxic colitis, or toxic megacolon
• Subjects with impaired consciousness that predisposes them to pulmonary aspiration
• Subjects who are undergoing colonoscopy for foreign body removal and decompression
• Subjects with pre-existing electrolyte disturbances, such as dehydration, or those secondary to the use of diuretics
• Subjects who are taking drugs that may affect electrolyte levels
• Subjects taking laxatives or prokinetic agents that refuse to discontinue these treatments for the duration of the study
• Subjects with known clinically significant electrolyte abnormalities such as hypernatremia, hyperphosphatemia, hypokalemia, or hypocalcemia
• Subjects who are pregnant or lactating, or intending to become pregnant during the study
• Subjects of childbearing potential who refuse a pregnancy test
• Subjects who are allergic to any preparation components
• Subjects who, in the opinion of the Investigator, should not be included in the study for any reason, including inability to follow study procedures
• Subjects who have participated in an investigational clinical, surgical, drug, or device study within the past 30 days