I pulled a random ingredient -- Uva Ursi Leaf -- from a random link you provided -- Colonix Intestinal Cleaner -- and got the following from drugdigest.org (which I admittedly can't vouch for.) All of that out of the way:
What side effects should I watch for?
Major Side Effects
In a dose of 6,000 mg (6 grams) or higher taken at one time, uva ursi may cause seizures or cyanosis (a blue tint to the skin caused by a lack of oxygen in the blood). Single doses of 30,000 mg (30 grams) or higher have been reported to cause death.
Other oral preparations that are high in tannin content have been associated with kidney or liver damage. Since uva ursi also contains tannins, using it may also present a risk for kidney or liver damage.
A case study of several individuals who regularly used large amounts of an oral product similar to uva ursi for many years, found that they had a higher incidence of tongue and lip cancer than expected. Cancers of the nose and esophagus may also be more likely in people who use large amounts of tannin-containing products for long amounts of time.
Less Severe Side Effects
Taking uva ursi has also been associated with:
Brownish or greenish urine
Nausea
Ringing in the ears
Upset stomach
http://www.drugdigest.org/DD/PrintablePages/herbMonograph/0,11475,4130,00.html