Colonoscopy is the preferred procedure to investigate any large-bowel disease in adults and children. In addition, colonoscopy is the current gold standard for colorectal cancer screening due to its high diagnostic capabilities and its unique feature that permits sampling and removal of pathology. For optimal performance and visualization of details, however, an adequate bowel preparation is essential. Inadequate bowel preparation is associated with cancelled procedures, prolonged procedure time, incomplete examination, increased cost and possibly complications, physician frustration and patient anxiety, but most importantly serving to impede colorectal cancer screening and surveillance.

A good bowel preparation would need a solution with a reasonable volume, acceptable taste, minimal diet restrictions, and easy to follow instructions; and would also need patients' adherence to the instructions and diet restrictions. Noncompliance of patients to the diet restrictions, the starting day of diet, the timing of drinking the solution, and other instructions play an important role in rendering the colon preparation inadequate.

Aim: The investigators aim, at assessing the influence of having a reminder mobile application on the compliance and adherence to instructions and diet and consequently on the quality of colon preparation.

Hypothesis: The investigators' hypothesis is that patients having a customized mobile App reminding them systematically about instruction and time of intake of the preparation will have a better adherence to the prep protocol and likely on the quality preparation than those given written and verbal instructions in clinic.

This is a randomized controlled trial that will include patients undergoing elective colonoscopy at the American University of Beirut Medical Center. Patients will be randomized into one of two study arms using a computer generated randomization list. 160 patients will be enrolled in total. All patients will be instructed by the study coordinator on the importance of adherence to the protocol in the leaflet emphasizing its importance to the colonoscopy quality. In addition, patients in Arm 2 will be given information about the application features. The application will have push notifications to inform patient on time of start of dietary changes, type of diet, time of preparing the solution, time of drinking the solution, reminder of their appointment, etc. All patients will then be interviewed by the research coordinator to evaluate the adherence to the assigned diet and compliance with the prep protocol as the main outcome and the ease of the application and the patient's attitude towards having such application as secondary outcomes. Based on the results of similar studies that assessed the use of software system to improve compliance, the investigators' sample size was a calculated assuming similar results. Calculations showed that 78 patients per arm will be enough to attain significance. The number 80 was chosen as attrition is presumed to be low. As for the statistical analysis, SPSS version 20.0 will be used for data entry and analysis.

Inclusion Criteria:

• Elective outpatient colonoscopy
• Consent to the study
• Owning a smartphone

Exclusion Criteria:

• Pregnant or lactating women
• Age less than 18 years
• Known Inflammatory bowel disease
• Significant gastroparesis
• Gastric outlet obstruction
• Ileus
• Known or suspected bowel obstruction or perforation
• Phenylketonuria
• Toxic colitis or megacolon
• Having a stoma
• Compromised swallowing reflex or mental status
• Psychiatric disease or known or suspected poor compliance
• Severe chronic renal failure (creatinine clearance <30 mL/minute)
• Severe congestive heart failure (New York Heart Association [NYHA] class III or IV)
• Dehydration
• Laxative use or dependency
• Chronic constipation (<3 spontaneous bm/week)
• Uncontrolled hypertension (systolic blood pressure ≥170 mm Hg, diastolic blood pressure ≥100 mm Hg)