Be warned, because one of the most misleading labels are those for 100% cranberry juice. Chances are if you're looking to buy such a product, what you want is 100% cranberry unsweetened with no sugar added, correct?
What you actually end up getting is something that is sweetened, but just with something different than cane sugar/high fructose corn syrup.
How can they get away with this? Well if you look closely at the order of words in the label, you will see they aren't actually claiming it's only cranberry. Rather, they're claiming "100% juice" in close proximity to the word "cranberry." Of course many of us assume this means 100% cranberry but what it almost always means is a 100% blend of cranberry + one or more other juices used to sweeten it, such as apple, pear, grape, pomegranate, etc.
So it is true that there's no refined sugar added, but the amount of sugar (coming from the other juices) is often equal to and sometimes even greater than the versions sweetened with refined sugar. For example, an 8 ounce serving of Ocean Spray 100% juice cranberry contains 28 grams of sugar, mostly coming from the grape, apple, and pear juices which are added. Contrast that to their cranberry cocktail - sweetened with cane or beet sugar - which also contains 28 grams of sugar. So even though one version is made with 100% juice, the glycemic impact it has on your blood sugar will more or less be the same.
If you want it with no sweetening of any kind, this is what you're looking for.
USDA Database for the Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods, Release 2 - Prepared by Nutrient Data Laboratory, Beltsville Human Nutrition Research Center (BHNRC), Agricultural Research Service (ARS), U.S. Department of Agriculture (USDA) - May 2010