To compare intestinal preparation with Lactulose vs. Sodium Phosphate as the better agent for performing high-quality colonoscopies at the Civil Hospital Fray Antonio Alcalde and the Civil Hospital Juan I. Menchaca, both in Guadalajara, Mexico; as well as Hospital Santo Tomás in Panama City, Panama; and Hospital Gustavo Nelson Collado Ríos in Chitré, Panama; during the period from April 1, 2025, to November 30, 2025. The comparison will focus on colonoscopy quality, patient tolerance, satisfaction, and electrolyte changes, using the agents orally as part of the bowel preparation prior to the colonoscopy procedure.

Randomized Double-Blind Clinical Trial conducted from April 1, 2025, to November 30, 2025, involving patients scheduled for outpatient colonoscopy at the Coloproctology Departments of the Civil Hospital Fray Antonio Alcalde, Civil Hospital Juan I. Menchaca (both in Guadalajara, Mexico), Hospital Santo Tomás in Panama City, Panama, and Hospital Gustavo Nelson Collado Ríos in Chitré, Panama.

Patients undergoing elective or emergency therapeutic colonoscopies, as well as those with certain medical conditions or pregnancy, were excluded from the study. Factors related to bowel preparation were considered, with particular emphasis on the characteristics of the chosen preparation agent, its effects, and findings observed during each patient's colonoscopy. All data were collected in a database, which will be shared via a digital platform using the SPSS statistical package for data analysis, followed by the development of conclusions.

Inclusion Criteria:

• Indication for Scheduled Colonoscopy: Participants must have a valid clinical indication for undergoing a scheduled colonoscopy, such as part of a colorectal cancer screening program, evaluation of gastrointestinal symptoms, or follow-up of previously diagnosed colorectal conditions.
• Ability to Provide Informed Consent: Participants must have the physical and mental capacity to understand the nature of the study and voluntarily provide informed consent to participate.

Exclusion Criteria:

• History of Intestinal Obstruction: Participants with a known or suspected history of intestinal obstruction will be excluded due to the potential risks associated with the administration of bowel preparation agents.
• Known Intolerance to Lactulose or Sodium Phosphate: Participants with a known intolerance to lactulose or sodium phosphate will be excluded due to the risk of severe adverse reactions.
• Pregnancy and Lactation: Pregnant or breastfeeding women will be excluded due to the lack of safety data on bowel preparation agents in this population.
• Interfering Clinical Conditions (Comorbidities): Participants with medical conditions that could interfere with study participation or affect the interpretation of results will be excluded, such as decompensated heart failure, chronic renal or liver disease, and a history of colonic resection.

The participants'/patients' data will be recorded only by hospital record and coded ID in the study database, no personal information wil be recorded. If necessary, additional data that may be used in the database will also be considered.