Many species of Vaccinium have a long history of use for medicinal purposes. All parts of the plant have been used with the fruit being favoured in Europe while the leaves, stems and bark are more widely used by Native Americans.

As far back as the twelfth century St Hildegard of Bingen, the first woman to write a Herbal, wrote that Bilberry fruits were good for inducing menstruation. The 16th century German herbalist, Hieronymus Bock wrote that the berries were useful for the treatment of bladder stones, and lung and liver disorders.
Berries were used fresh or dried for winter use and then soaked in water to make infusions or syrups such as that used for centuries for the treatment of coughs.
In the 18th century, especially in Germany, bilberries, probably V. myrtillus became a valuable resource for herbalists and physicians, using extracts from dried berries as an infusion or tisane. The latter was used as an astringent for treating diarrhoea, as a diuretic, to prevent scurvy and as a mouthwash to soothe mouth ulcers as well as in the treatment of gout and rheumatism, and even to relieve the symptoms of typhoid fever.

During WW2 when British Royal Air Force pilots were on nighttime bombing missions they reported that their sight was improved after eating bilberry jam. This report led to the first laboratory and clinical research, in the 1960's into the effects of bilberry fruit extracts on the eyes and indeed on the wider subject of the whole vascular system.

Air traffic controllers, airline pilots and truck drivers have also reported improved night time vision when given extracts of bilberry fruit.

Italian researchers, working between 1982 and 1987, reported that 76% of patients in their trials experienced a marked improvement in their myopia (short-sightedness) after being given 150mg per day of a blueberry extract, plus vitamin A, for 15 days. They also reported that there was a significant reduction or disappearance of haemorrhages in the retina of the eyes of diabetes sufferers given a higher dose of extract for 30 days to one year.

The red, blue, or violet colour of the skin of Vaccinium fruit is due to organic chemicals; and the anthocyanosides, which derive from these are the key to the beneficial effects of the fruit. At least 15 different anthocyanoside compounds have been identified from bilberry extracts. In addition there are up to 7% tannins, several alkaloids, twelve different phenolic acids and three glycosides which may all play a positive role for medicinal benefit.

The most effective medicinal use for bilberry/blueberry extract appears to be for improving micro-circulation, thus its effects on the capillaries serving the eyes, mucous membranes of the digestive and pulmonary systems.

Improved capillaries also help to improve circulation to the connective tissues, which should help arthritis sufferers. Water retention in the legs, and varicose veins, general bruising and haemorrhoids are all problems that, according to the research so far, can be treated successfully with bilberry extract.

There are no reports of adverse effects due to the use of bilberry extract, nor are any expected. The long history of use for food is a good indication of its safety. The extract is given orally, but there are plans to make an injectable extract in the future. In North America the native American tribes have used various species of Vaccinium for medicinal purposes, using every part of the plant; flowers, fruit, leaves, young shoots, bark and even occasionally roots.

While not quite a "cure all" it is apparent that where cures involving the many problems where blood and its circulation are concerned Blueberry and Cranberry plants have provided important infusions.