Picolax is used to cleanse the lower bowel in preparation for endoscopic, barium enema, X-ray or surgical gastrointestinal examination. It does this by acting in the intestine and colon causing a watery bowel motion which evacuates the bowel.
It is important to have an empty, clean bowel so that your doctor can see it clearly.
You should discuss with your doctor what is going to happen before you have the procedure. Your doctor however may prescribe Picolax for another purpose.