There are four major varieties of cranberries: European, American, Mountain, and Highbush.

• American. This variety is the most common in the United States. The U.S. Department of Agriculture uses this variety as the standard for fresh cranberries and cranberries used for juice. This variety is bright red.
  
  
• European. This variety is smaller than the American and is eaten less often than other varieties. It is primarily ornamental.
  
  
• Mountain. This variety is approximately ¼ to ½ inch in diameter and is bright red to dark red. It is occasionally found in markets.
  
  
• Highbush. This variety is primarily used for jellies, jams, and sauces. It is also used as an ornamental fruit.

Cranberries contain proanthocyanidins (PACs) that can prevent the adhesion of certain of bacteria, including E. coli, associated with urinary tract infections. It is also thought that the anti-adhesion properties of cranberries may inhibit the bacteria associated with gum disease and stomach ulcers. 

Cranberries also contain quinic acid which helps prevent kidney stones. In patients who have had recurrent kidney stones, cranberry juice has been shown to reduce the amount of ionized calcium in their urine by more than 50 percent.

Cranberries also help in lowering cholesterol levels and are a good source of dietary fiber and vitamin C.