My son 18yrs old with bloody stools. he was schedule for a sigmoidoscopy.,using fleet enema (sodium bisphosphate). he don't want to go through this. what's the alternative?

Bowel prep: Some centers will not even attempt a procedure like a sigmoidoscopy unless the patient is willing to follow the preparation protocol. That said, they may be willing to do so if the patient does a significant bowel prep using a bottle of magnesium citrate or similar agent. I would call the center and see. The exam is worthless unless the fecal material is removed and the colon can be seen.