Bowel movement problem

Last week,when I called at home,my father told me that he wanted to try a colon cleanse product.For number of days now,he is experiencing of having a problem in his bowel movement.Someone told him that what if he will use a colon cleanse product because it will help clear the toxins in the body and thus help his bowel movement.I told my father that he rather go to the doctor and know what's the problem.I even told him to ask the doctor if it's ok and safe to use a colon cleanse product.I don't want him to take any products without the doctor's prescription.