Green Tea

• Green tea, made from unfermented tea leaves of the Camellia sinensis plant, has become quite popular. Green teas have the least caffeine of any tea. Its positive side effects are high vitamin C content, high antioxidant content and higher polyphenols. In higher quantities, green teas have more of a tendency to cause stomach upset.
  
  

Oolong Tea

• Oolong teas are made from the semi-fermented leaves of the Camellia sinensis. They are richer in flavor, but contain less vitamin C and fewer antioxidants and polyphenols. However, they are still very high in the last two. Oolong teas, like green teas, can cause high stomach acidity and stomach upset when a person drinks too much.
  
  

Black Tea

• Black tea, which is called "red tea" in China, is a fully fermented tea made from the Camellia sinensis plant. It has the highest caffeine of any tea made from the Camellia sinensis plant, and, it has lower antioxidant and polyphenol content. Black tea tends to settle better when consumed in larger quantities and has less of an effect on the stomach, especially when sweetened.
  
  

Pu-Erh Tea

• Pu-erh tea is made from the ancient, large leaved version of the Camellia sinensis, the ancestor of the modern tea plant. Chinese medicine lists pu-erh as a tea that reduces cholesterol, and modern research has supported this assertion. It is very high in caffeine and has virtually no side effects on the stomach.
  
  

Blended Teas

• Teas can be blended with other medicinal and flavoring agents. Common blending items are ginseng, various flowers and various Chinese herbs. Floral teas have no side effects, but teas blended with ginger and ginseng may have side effects on the chi, in addition to the tea side effects.