Colon Cleansing?

This was recently on Good Morning America Health. Is colon cleansing good? or bad? I've heard that colon cleansing is good, good for your body and your mental health. It cleans out all the toxins.

Dr Greenwald, who is a gastroenterologist, says that it isn't healthy.

What is a colon cleanse?
Clean waste materials out of their colon. Use a tube and flush out everything from the colon.
60-80L (15-20 gallons) of water.
Solutions with additives, teas/herbs.

Why do people do colon cleanses?
1. To lose weight quickly.
2. Feel like they need to purge their body of toxins and waste.

3. Preparation for surgery and colonoscopy.

Side effects?
Mild: abdominal pain, cramping, vomiting, bloating, nausea
Severe: dehydration, damage to kidneys, change of chemical balance, inflammation of pancreas and perforate colon.

Why not healthy?
It just comes right back. You need to change your lifestyle (in=out).
Colon purge eliminates good bacteria in colon. (comes back)

Other options?
Balanced diet.
Regular exercise.
20-35g of fiber/day.
Screen for colon cancer (50+).

What I got from this is that if you really want to be healthy you do a colon cleanse and implement a good complete change of lifestyle after it, otherwise - it's unhealthy and useless.