The purpose of this study is to determine any significant differences in the efficacy and acceptability between CitraFleet and Klean Prep® (polyethylene glycol) for the preparation of gastrointestinal subjects undergoing a colon examination.

The composite principal objective of the current study will therefore be, to determine any significant differences in the joint variable of efficacy and acceptability between CitraFleet and Klean Prep® (polyethylene glycol) for the preparation of subjects undergoing a colon examination.

The evaluation will be carried out by two blinded assessors, independent of the investigator who performed the procedure (endoscopist investigator). It will be assessed from images of different sections of the colon: cecum, ascending, transverse, descending and rectum and subsequent confirmation by Principal Investigator if an agreement has been reached between the two blinded assessors or whether it is necessary to reach consensus.

The evaluation of the subject's acceptability will be assessed using a 5 point scale which assesses the difficulty of taking the product, the degree of discomfort caused by it, and the taste of the drug.

The secondary objective is to evaluate the safety of CitraFleet.

In addition a second exploratory arm of CitraFleet was included in this study (CitraFleet Exploratory arm). The study is not powered to make formal statistical comparisons for this arm. Exploratory assessment of this arm against the main CitraFleet regimen and Klean-Prep will be made in order to run future trials design with this schedule.

Inclusion Criteria:

• Subjects who are between 18 and 80 years of age.
• Subjects undergoing complete colonoscopy and therefore require prior preparation with either Klean Prep® or CitraFleet.
• Subjects capable of maintaining appropriate oral hydration during the intestinal preparation process.
• Subjects that have provided written informed consent.
• Subjects in whom the use of any of the study drugs (KleanPrep®,CitraFleet) is not contraindicated.
• Subjects who can communicate with the study personnel and comply with study requirements.
• Subjects undergoing a complete exploratory diagnostic colonoscopy for the first time.

Exclusion Criteria:

• Severe renal insufficiency.
• Ascites.
• Congestive heart failure.
• Gastrointestinal obstruction, gastric retention, intestinal perforation and/or ileus.
• Megacolon and/or toxic colitis.
• Nausea and/or vomiting and/or abdominal pain.
• Severe dehydration.
• Hypermagnesemia.
• Rhabdomyolysis.
• Pregnant women.
• Subjects who have participated in a clinical trial in the previous 30 days.
• Abdominal surgery for any acute process (for example acute appendicitis).
• Active inflammatory intestinal disease.
• Known allergy to any of the active ingredients or excipients of the study drugs.
• Subjects not providing written informed consent.
• Subjects not complying with all of the inclusion criteria.