Wintergreen is a group of plants. Wintergreen once commonly referred to plants that remain green (continue photosynthesis) throughout the winter. The term evergreen is now more commonly used for this characteristic. Most species of the shrub genus Gaultheria demonstrate this characteristic and are called wintergreens in North America, the most common generally being the Eastern Teaberry (Gaultheria procumbens). Wintergreen berries, from Gaultheria procumbens, are used medicinally. Native Americans brewed a tea from the leaves to alleviate rheumatic symptoms, headache, fever, sore throat and various aches and pains. During the American Revolution, wintergreen leaves were used as a substitute for tea, which was scarce. Wintergreen is a common flavoring in American products ranging from root beer, chewing gum, mints and candies to smokeless tobacco such as dipping tobacco (American 'dip' snuff) and snus.