"The bilberry bush is a relative of the blueberry and is native to many areas, including the Rocky Mountains and regions of Europe and Asia. Its berries and leaves have been used for medicinal purposes since the Middle Ages for a variety of conditions, including diarrhea, scurvy, infections, burns, and diabetes. During World War II, British pilots ate bilberry jam, thinking it would improve their night vision. Today, bilberry is used as a dietary supplement for cardiovascular conditions, diarrhea, urinary tract infections, eye problems, diabetes, and other conditions. Bilberry extract is sold in tablets, capsules, and drops, and the berries are sold dried and as a powder. The leaves are made into teas."