Vaccinium myrtillus is found natively in Europe, northern Asia, Greenland, Western Canada, and the Western United States. It occurs in the wild on heathlands and acidic soils. Its berry has been long consumed in the Old World. It is related to the widely cultivated North American blueberry.
Vaccinium myrtillus has been used for nearly 1,000 years in traditional European medicine. Vaccinium myrtillus fruits have been used in the traditional Austrian medicine internally (directly or as tea or liqueur) for treatment of disorders of the gastrointestinal tract and diabetes. Herbal supplements of V. myrtillus (bilberry) on the market are used for circulatory problems, as vision aids, and to treat diarrhea and other conditions. The United States' National Institutes of Health (NIH) cautions, "Theres not enough scientific evidence to support the use of bilberry for any health conditions."
In cooking, the bilberry fruit is commonly used for the same purposes as the American blueberry such as pies, cakes, jams, muffins, cookies, sauces, syrups, juices, and candies.
In traditional medicine, bilberry leaf is used for different conditions, including diabetes. The NIH rates it as "possibly effective for problems with the retina of the eye in people with diabetes or high blood pressure".
Since many people refer to "blueberries", no matter if they mean the bilberry (European blueberry) Vaccinium myrtillus or the American blueberries, there is a lot of confusion about the two closely similar fruits. One can distinguish bilberries from their American counterpart by the following differences:
bilberries have dark red, strongly fragrant flesh and red juice that turns blue in basic environments; blueberries have white or translucent, mildly fragrant flesh
bilberries grow on low bushes with solitary fruits, and are found wild in heathland in the Northern Hemisphere; blueberries grow on large bushes with the fruit in bunches
bilberries are usually harvested from wild plants, while blueberries are usually cultivated and are widely available commercially
cultivated blueberries often come from hybrid cultivars, developed about 100 years ago by agricultural specialists, most prominently by Elizabeth Coleman White, to meet growing consumer demand; since they are bigger, the bushes grow taller, and are easier to harvest
bilberry fruit will stain hands, teeth and tongue deep blue or purple while eating; it was used as a dye for food and clothes, while blueberries have flesh of a less intense color, and are thus less staining
when cooked as a dessert, bilberries have a much stronger, more tart flavor and a rougher texture than blueberries
Adding to the confusion is the fact there are also wild American blueberry varieties, sold in stores mainly in the USA and Canada. These are uncommon outside of Northern America. Even more confusion is due to the huckleberry name, which originates from English dialectal names 'hurtleberry' and 'whortleberry' for the bilberry.