Diarrhea and wounds
Bilberry (Vaccinium myrtillus) has been used in traditional European medicine for nearly a thousand years, primarily to treat diarrhea. Bilberry fruit contains high concentrations of tannins, substances that act as both an anti-inflammatory and an astringent. The latter quality in particular may help wounds heal more quickly. Bilberry is believed to help people with diarrhea by reducing the intestinal inflammation associated with the condition.

Diabetes
Bilberry leaves have traditionally been used to control blood sugar levels in people with diabetes. A couple of modern day reports of a few individuals with type 2 (adult onset) diabetes as well as animal studies suggest that this traditional use may have merit. Rigorous scientific studies are needed.

Antioxidants
A close relative of the cranberry, bilberry fruits contain flavonoid compounds called anthocyanidins. Flavonoids are plant pigments that have excellent antioxidant properties. This means that they scavenge damaging particles in the body known as free radicals and have been shown to help prevent a number of long-term illnesses such as heart disease, cancer, and an eye disorder called macular degeneration (a disease of the retina that can lead to blindness; see Visual Disturbances listed below). Animal studies have found that anthocyanidins may strengthen blood vessels, improve circulation, and prevent the oxidation of LDL ("bad") cholesterol, a major risk factor for atherosclerosis (plaque in blood vessels that leads to blockage and, therefore, heart attack and stroke). Research in people is needed.

Chronic fatigue syndrome
Some experts propose that bilberry may relieve the symptoms of chronic fatigue syndrome because of its antioxidant properties.

Ulcers
Studies in rats have found that anthocyanidins from bilberry fruits help prevent stomach ulcers caused by a variety of factors including stress, medications, and alcohol. Whether this will translate into help for people requires research.

Visual disturbances
Anthocyanidins found in bilberry fruits may also be useful for people with vision problems. During World War II, British fighter pilots reported that bilberries improved their nighttime vision and helped them quickly adjust to darkness. A recent study, however, comparing a bilberry extract of anthocyanidins to placebo in young men with normal vision did not confirm any improvement in night vision from this supplement. The study only included 12 men. Therefore, more research is needed to know whether the long standing stories of improvement in night vision from bilberry for some individuals is scientifically true or not.

Today, it is believed that anthocyanidins may help protect the retina, the nerve layer that lines the back of the eye and sends nerve impulses to the visual areas of the brain. Studies conducted in the 1960s, 70s, and 80s suggest that the anthocyanidins contained in bilberry fruit preparations improve symptoms of a variety of visual disturbances including nearsightedness, cataracts, and macular degeneration.

Bilberry is a shrub that grows to about 16 inches in height. It has oval, pointed leaves and small pink and white flowers, which bloom from April through June. In the late summer, its dark purple berries are ripe to pick. Bilberry is a relative of blueberry, cranberry, and huckleberry, and its fruit looks and tastes much like the American blueberry.

The key compounds in bilberry fruit are called anthocyanidins. These compounds help build strong capillaries and improve circulation to all areas of the body. They also prevent blood platelets from clumping together (helping to reduce the risk of blood clots which may lead, for example, to heart attack or stroke). On the other hand, bilberry fruit is also rich in tannins, a substance that acts as an astringent, thereby helping bleeding to stop. The tannins and anthocyanidins, therefore, may balance each other out when the whole bilberry fruit is used for medicinal purposes.

Anthocyanidins also boost the production of rhodopsin, a pigment that improves night vision and helps the eye adapt to light changes. The tannins have anti-inflammatory properties and may help control diarrhea.

Bilberries may be eaten fresh or in dried forms. Fresh or dried berries as well as the leaves of the bilberry plant may be used to make bilberry tea. Bilberry extract should be standardized to contain 25% anthocyanidins. The extract contains the highest percentage of anthocyanidins, making it the most potent form of bilberry.

The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, contain active substances that can trigger side effects and that can interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a practitioner knowledgeable in the field of botanical medicine.

Pediatric

Bilberry has been used safely in children 2 years of age and older for the treatment of diarrhea:

• 4 to 8 grams of crushed, dried bilberry should be added to 150 mL (2/3 of a cup) of cold water and brought to a boil for 10 minutes; the preparation should be strained while hot. Children then drink this preparation several times daily until diarrhea resolves.

Adult

• Diarrhea: 5 to 10 grams of crushed dried bilberries in 150 mL (2/3 of a cup) cold water, brought to a boil for 10 minutes, then strained.
• Eye conditions and circulation: standardized bilberry extract (with 25% anthocyanidin) in encapsulated form, dosage of 480 milligrams a day in two to three divided doses. Reduce to 240 milligrams per day once symptoms improve (maintain this dosage to help prevent these conditions).
• Diabetes: Pour boiling water over 1 g (approximately 1½ tsp) bilberry leaf and strain after 10 to 15 minutes. People with in particular diabetes should only drink bilberry tea under the supervision of a healthcare provider.
• Ulcer prevention: 20 to 40 milligrams bilberry extract three times a day, 2 to 4 mL tincture (1:5) three times a day, or one half cup of fresh bilberries.

Because of the potential for side effects and interactions with medications, bilberry extracts and anthocyanidin preparations should be taken only under the supervision of a knowledgeable healthcare provider.

Bilberry fruit and extract are considered generally safe, with no known side effects. Bilberry leaf is safe with appropriate usage, but should not be taken in large quantities over an extended period of time because it may become toxic.

Blood-thinning medications, anticoagulants
In theory, because the anthocyanidins in bilberry may inhibit blood from clotting, there may be an increased risk of bleeding in those taking anthocyanidin extracts from bilberry along with blood thinners, particularly warfarin. This has not been tested scientifically, but those taking warfarin or other blood thinners in the same class, known as anticoagulants, should be very careful if considering use of bilberry and should be followed closely by a doctor who will check your INR (a measurement to indicate, in part, your risk of bleeding).

There has been one case report of a woman taking many herbs and supplements, including bilberry, experiencing a serious bleed following surgery for breast cancer. The other herbs and supplements she was taking that may have contributed to the risk of bleeding include ginkgo, ginseng, and vitamin E.

The whole bilberry fruit, therefore, which contains both anthocyanidins and tannins (that may help stop bleeding) is likely safer if you are on a blood thinner than the isolated anthocyanidin extracts.

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