a Low-residue Diet for Bowel Preparation

Inclusion Criteria: * Patients whose age is between 18-65. * Patients who have indications for screening, surveillance and diagnostic colonoscopy. * Patients who have signed inform consent form Exclusion Criteria: * subjects who had known or suspected heart failure, stroke or renal failure; * subjects who had a history of colon surgery or inflammatory bowel disease; * subjects who Patients with had digestion or absorption dysfunction or any dietary restriction due to various reasons; * subjects who had a history of hypersensitivity to any ingredients of laxatives or soy products; * subjects who had high risk factors for bowel preparation such as chronic constipation, Body Mass Index (BMI) greater than 30 or BMI less than 18 Kg/m2, diabetes, spinal cord injury, or use of medications affecting bowel motility within a week; * subjects who had participated in another interventional clinical trial in the previous 60 days; * pregnant or lactating women and those planning to become pregnant.