Colonoscopy is one of the most common methods for the diagnosis and treatment of lower gastrointestinal tract diseases. Before colonoscopy it is required to prepare the colon. The patient will receive a bowel preparation solution containing magnesium sulfate, potassium sulfate and sodium sulfate. After this, only clear liquids will be permitted for four hours before the procedure. However, even with this preparation, the mucosal visualization, is impaired by the presence of stools, foam, or bubbles in most of the cases. Intraluminal foam and bubbles can hamper endoscopic visibility, potentially missing lesions and extending time of procedure.  To improve visualization of the colonic mucosa, it is possible to administer an oral solution of defoaming agent such as Simethicone prior to the procedure. Simethicone is a defoaming agent which decreases surface tension, leading to coalescing of foam and bubbles. Simethicone is not absorbed from the gastrointestinal tract and is not attached to other drugs, and rarely has adverse effects. It also helps reducing the time to flush with water to clear the mucous and also reduces the total time consumed to finish the endoscopy procedure.  Studies have demonstrated that simethicone enhances visualization during upper gastrointestinal endoscopy. Furthermore, several studies have reported that the addition of simethicone to bowel preparation prior to colonoscopy and small bowel capsule endoscopy can augment endoscopic mucosal visibility, improve diagnostic accuracy, and enhance endoscopist satisfaction. Despite its potential benefits, the utilization of this solution for colonoscopy has not been evaluated in Indian populations. 

The Primary Objective of this study is to evaluate the impact of Simethicone on enhancing colonoscopy preparation quality, as determined by the Boston Bowel Preparation Scale (BBPS) and the Colon Endoscopic Bubble Scale (CEBuS). The Secondary Objective of this study is to assess and compare the procedure time between the two groups. This is a single-center, double-blind, placebo-controlled, prospective randomized controlled trial conducted at the Cancer Institute (WIA), Adyar, Chennai.