The billberry is well-known for its tasty blue-dyeing fruits. Historically the leaves and fruits were used to treat diabetes, cardiovascular diseases, dementia and cancer. Antidiabetic properties of the plant are attributed mostly to the content of anthocyanins and polyphenols. These compounds have proven their antidiabetic potential in various studies. Their mechanism of action is an increase in insulin secretion (anthocyanin pelargonidin), reduction of insulin resistance (anthocyanin cyanidin-3-glucoside), glucose resorption from the GIT (polyphenols) and enhancement of beta-cells regeneration. Besides these effects, anthocyanins contribute to the improvement of the lipid spectrum and have antioxidant, anti-inflammatory and cardioprotective activities. Antidiabetic effects of anthocyanin cyanidin-3-galactoside were compared to acarbose (synergistic effect), hypocholesterolemic activity of cyanidin-3-O-glucoside to atorvastatin (synergistic effect) and hypolipidemic properties of blueberry leaf extract to ciprofibrate (extract has a lower effect). However, in many preclinical and clinical studies different species of the Vaccinium genus and other plants with asimilar effect as the billberry were also assessed. Therefore, in order to convincingly assess the efficacy and safety of blueberry herbal medicines more studies are necessary. Such studies should shed light into the variety of anthocyanins, their particular effects and optimal doses and compare their effects with intake of foods generally rich in anthocyanins.Key words: billberry Vaccinium myrtillus diabetes mellitus phytotherapy antocyanines.