Bilberry is a plant. The dried, ripe fruit and leaves are used to make medicine.
Bilberry is used by mouth to treat poor circulation that can cause the legs to swell. Some people take bilberry for diabetes, high blood pressure, gout, urinary tract infections (UTIs), and many other conditions. But there is no good scientific research to support these other uses.
Bilberry is also sometimes used by mouth to treat eye conditions such as disorders of the retina, cataracts, nearsightedness, and glaucoma. There is some evidence that bilberry may help retinal disorders, but there is no good scientific evidence that bilberry is effective for treating other eye conditions.
In fact, bilberry was once commonly used for improving night vision. During World War II, British pilots in the Royal Air Force ate bilberry jam to improve their night vision, but later research showed it probably didn’t help.
Bilberry is sometimes applied directly to the inside of the mouth for mild mouth and throat soreness.