Cell phone retell the instruction of bowel preparation on the day before colonoscopy would help patient to prepare for colonoscopy and improve the quality of the bowel preparation.

Colonoscopy is the gold standard in the diagnosis of colorectal disease. The success of colonoscopy depends on high-quality bowel preparation by patients. Inadequate bowel cleansing reduces the speed, the cecal intubation rate, and the number of polyps detected. It also increases costs, mostly due to repeated procedures. The quality of bowel cleansing has remained suboptimal even though numerous different products and regimens have been tested and compared in no fewer than six meta-analyses. Therefore, a completely different approach to improve precolonoscopy bowel cleansing is welcome.

There are many factors effect the bowel preparation such as age, cirrhosis diabetes, drug compliance, cerebral infarction, dementia, history of major surgery. 20% of patients with poor bowel preparation were due to bad compliance. Studies found that addressing patient perceptions with an inexpensive and simple booklet based on the Health Belief Model improved preparation quality. We assume that doctor retelling the instruction of bowel preparation by cell phone on the day before colonoscopy would help patient to prepare for colonoscopy and improve the quality of the bowel preparation.

Inclusion Criteria:

• patients undergoing colonoscopy

Exclusion Criteria:

• disturbance of water and electrolyte
• history of colorectal surgery
• severe colonic stricture or obstructing tumor
• known or suspected bowel obstruction or perforation
• toxic colitis or megacolon
• dysphagia
• compromised swallowing reflex or mental status
• significant gastroparesis or gastric outlet obstruction or ileus
• severe chronic renal failure (creatinine clearance <30 mL/minute)
• severe congestive heart failure (New York Heart Association class III or IV)
• uncontrolled hypertension (average systolic blood pressure >170 mm Hg, average diastolic blood pressure >100 mm Hg)
• pregnant or lactating women
• patients who cannot give informed consent